diff --git a/doc/source/tech_note/Fire/CLM50_Tech_Note_Fire.rst b/doc/source/tech_note/Fire/CLM50_Tech_Note_Fire.rst index 0483567ff5..662e574666 100644 --- a/doc/source/tech_note/Fire/CLM50_Tech_Note_Fire.rst +++ b/doc/source/tech_note/Fire/CLM50_Tech_Note_Fire.rst @@ -3,7 +3,7 @@ Fire ======== -The fire parameterization in CLM contains four components: non-peat fires outside cropland and tropical closed forests, agricultural fires in cropland, deforestation fires in the tropical closed forests, and peat fires (see :ref:`Li et al. 2012a `, :ref:`Li et al. 2012b `, :ref:`Li et al. 2013 `, :ref:`Li and Lawrence 2017 ` for details). In this fire parameterization, burned area is affected by climate and weather conditions, vegetation composition and structure, and human activities. After burned area is calculated, we estimate the fire impact, including biomass and peat burning, fire-induced vegetation mortality, adjustment of the carbon and nitrogen (C/N) pools, and fire emissions. +The fire parameterization in CLM contains four components: non-peat fires outside cropland and tropical closed forests, agricultural fires in cropland, deforestation fires in the tropical closed forests, and peat fires (see :ref:`Li et al. 2012a `, :ref:`Li et al. 2012b `, :ref:`Li et al. 2013 `, :ref:`Li and Lawrence 2017 `, :ref:`Li et al. 2024b ` for details). In this fire parameterization, burned area is affected by climate and weather conditions, vegetation composition and structure, and human activities. After burned area is calculated, we estimate the fire impact, including biomass and peat burning, fire-induced vegetation mortality, adjustment of the carbon and nitrogen (C/N) pools, and fire emissions. .. _Non-peat fires outside cropland and tropical closed forest: @@ -29,9 +29,9 @@ Fire counts :math:`N_{f}` is taken as .. math:: :label: 23.2 - N_{f} = N_{i} f_{b} f_{m} f_{se,o} + N_{f} = N_{i} f_{b} f_{m} f_{se,o} f_{topo} -where :math:`N_{i}` ( count s\ :sup:`-1`) is the number of ignition sources due to natural causes and human activities; :math:`f_{b}` and :math:`f_{m}` (fractions) represent the availability and combustibility of fuel, respectively; :math:`f_{se,o}` is the fraction of anthropogenic and natural fires unsuppressed by humans and related to the socioeconomic conditions. +where :math:`N_{i}` ( count s\ :sup:`-1`) is the number of ignition sources due to natural causes and human activities; :math:`f_{b}` and :math:`f_{m}` (fractions) represent the availability and combustibility of fuel, respectively; :math:`f_{se,o}` is the fraction of anthropogenic and natural fires unsuppressed by humans and related to the socioeconomic conditions; :math:`f_{topo}` represents the influence of topography on fires. :math:`N_{i}` (count s\ :sup:`-1`) is given as @@ -66,7 +66,7 @@ Fuel availability :math:`f_{b}` is given as \begin{array}{cc} {} & {} \end{array}\begin{array}{c} {B_{ag} B_{up} } \end{array}\right\} \ , -where :math:`B_{ag}` (g C m\ :sup:`-2`) is the biomass of combined leaf, stem, litter, and woody debris pools; :math:`B_{low}` = 105 g C m :sup:`-2` is the lower fuel threshold below which fire does not occur; :math:`B_{up}` = 1050 g C m\ :sup:`-2` is the upper fuel threshold above which fire occurrence is not limited by fuel availability. +where :math:`B_{ag}` (g C m\ :sup:`-2`) is the biomass of combined leaf, stem, litter, and woody debris pools; :math:`B_{low}` = 75 g C m :sup:`-2` is the lower fuel threshold below which fire does not occur; :math:`B_{up}` = 825 g C m\ :sup:`-2` is the upper fuel threshold above which fire occurrence is not limited by fuel availability. Fuel combustibility :math:`f_{m}` is estimated by @@ -75,24 +75,24 @@ Fuel combustibility :math:`f_{m}` is estimated by f_{m} = {f_{RH} f_{\beta}}, \qquad T_{17cm} > T_{f} -where :math:`f_{RH}` and :math:`f_{\beta }` represent the dependence of fuel combustibility on relative humidity :math:`RH` (%) and root-zone soil moisture limitation :math:`\beta` (fraction); :math:`T_{17cm}` is the temperature of the top 17 cm of soil (K) and :math:`T_{f}` is the freezing temperature. :math:`f_{RH}` is a weighted average of real time :math:`RH` (:math:`RH_{0}`) and 30-day running mean :math:`RH` (:math:`RH_{30d}`): +where :math:`f_{RH}` and :math:`f_{\beta }` represent the dependence of fuel combustibility on relative humidity :math:`RH` (%) and root-zone soil wetness :math:`\beta` (fraction); :math:`T_{17cm}` is the temperature of the top 17 cm of soil (K) and :math:`T_{f}` is the freezing temperature. :math:`f_{RH}` is a weighted average of real time :math:`RH` (:math:`RH_{0}`) and 30-day running mean :math:`RH` (:math:`RH_{30d}`): .. math:: :label: 23.8 - f_{RH} = (1-w) l_{RH_{0}} + wl_{RH_{30d}} + f_{RH} = [(1-w) l_{RH_{0}} + wl_{RH_{30d}}]^{0.75} -where weight :math:`w=\max [0,\min (1,\frac{B_{ag}-2500}{2500})]`, :math:`l_{{RH}_{0}}=1-\max [0,\min (1,\frac{RH_{0}-30}{80-30})]`, and :math:`l_{{RH}_{30d}}=1-\max [0.75,\min (1,\frac{RH_{30d}}{90})]`. :math:`f_{\beta}` is given by +where weight :math:`w=\max [0,\min (1,\frac{B_{ag}-2500}{2500})]`, :math:`l_{{RH}_{0}}=1-\max [0,\min (1,\frac{RH_{0}-30}{85-30})]`, and :math:`l_{{RH}_{30d}}=1-\max [0.6,\min (1,\frac{RH_{30d}}{95})]`. :math:`f_{\beta}` is given by .. math:: :label: 23.9 f_{\beta } =\left\{\begin{array}{cccc} - {1} & {} & {} & {\beta\le \beta_{low} } \\ {\frac{\beta_{up} -\beta}{\beta_{up} -\beta_{low} } } & {} & {} & {\beta_{low} <\beta<\beta_{up} } \\ + {1} & {} & {} & {\beta\le \beta_{low} } \\ ({\frac{\beta_{up} -\beta}{\beta_{up} -\beta_{low} } })^{0.25} & {} & {} & {\beta_{low} <\beta<\beta_{up} } \\ {0} & {} & {} & {\beta\ge \beta_{up} } - \end{array}\right\} \ , + \end{array}\right. -where :math:`\beta _{low}` \ =0.85 and :math:`\beta _{up}` \ =0.98 are the lower and upper thresholds, respectively. +where :math:`\beta _{low}` \ and :math:`\beta _{up}` \ are the PFT-dependent lower and upper thresholds (:numref:`Table PFT-specific fire parameters`). For scarcely populated regions (:math:`D_{p} \le 0.1` person km :sup:`-2`), we assume that anthropogenic suppression on fire occurrence is negligible, i.e., :math:`f_{se,o} =1.0`. In regions of :math:`D_{p} >0.1` person km\ :sup:`-2`, we parameterize the fraction of anthropogenic and natural fires unsuppressed by human activities as @@ -128,26 +128,29 @@ which captures 73% of the observed MODIS fire counts with variable GDP in region to reproduce the relationship between MODIS fire counts and GDP. -.. _Average spread area of a fire: - -Average spread area of a fire -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -Fire fighting capacity depends on socioeconomic conditions and affects fire spread area. Due to a lack of observations, we consider the socioeconomic impact on the average burned area rather than separately on fire spread rate and fire duration: +The influence of topography on fires: .. math:: :label: 23.14 - a=a^{*} F_{se} + f_{topo} =\left\{\begin{array}{cc} + {0.004} & {elevation>2500m} \\ + {1} & {else} + \end{array}\right. -where :math:`a^{*}` is the average burned area of a fire without anthropogenic suppression and :math:`F_{se}` is the socioeconomic effect on fire spread area. +This indicates reduced burnability above 2500 m. It can be removed if CLM accounts in the future for the intense light exposure of Arctic C\ :sub:`3` grasses on plateaus, leading to greater carbon allocation to fine roots than to leaves and to reduced infiltration. + +.. _Average spread area of a fire: + +Average spread area of a fire +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -Average burned area of a fire without anthropogenic suppression is assumed elliptical in shape with the wind direction along the major axis and the point of ignition at one of the foci. According to the area formula for an ellipse, average burned area of a fire can be represented as: +Average burned area of a fire is assumed elliptical in shape with the wind direction along the major axis and the point of ignition at one of the foci. According to the area formula for an ellipse, average burned area of a fire can be represented as: .. math:: :label: 23.15 - a^{*} =\pi \frac{l}{2} \frac{w}{2} \times 10^{-6} =\frac{\pi u_{p}^{2} \tau ^{2} }{4L_{B} } (1+\frac{1}{H_{B} } )^{2} \times 10^{-6} + a =\pi \frac{l}{2} \frac{w}{2} \times 10^{-6} =\frac{\pi u_{p}^{2} \tau ^{2} }{4L_{B} } (1+\frac{1}{H_{B} } )^{2} \times 10^{-6} where :math:`u_{p}` (m s\ :sup:`-1`) is the fire spread rate in the downwind direction; :math:`\tau` (s) is average fire duration; :math:`L_{B}` and :math:`H_{B}` are length-to-breadth ratio and head-to-back ratio of the ellipse; 10 :sup:`-6` converts m :sup:`2` to km :sup:`2`. @@ -172,7 +175,7 @@ The fire spread rate in the downwind direction is represented as u_{p} =u_{\max } C_{m} g(W) -(:ref:`Arora and Boer, 2005`), where :math:`u_{\max }` (m s\ :sup:`-1`) is the PFT-dependent average maximum fire spread rate in natural vegetation regions; :math:`C_{m} =\sqrt{f_{m}}` and :math:`g(W)` represent the dependence of :math:`u_{p}` on fuel wetness and wind speed :math:`W`, respectively. :math:`u_{\max }` is set to 0.33 m s :sup:`-1`\ for grass PFTs, 0.28 m s :sup:`-1` for shrub PFTs, 0.26 m s\ :sup:`-1` for needleleaf tree PFTs, and 0.25 m s\ :sup:`-1` for other tree PFTs. :math:`g(W)` is derived from the mathematical properties of the ellipse and equation :eq:`23.16` and :eq:`23.17`. +(:ref:`Arora and Boer, 2005`), where :math:`u_{\max }` (m s\ :sup:`-1`) is the PFT-dependent average maximum fire spread rate in natural vegetation regions (:numref:`Table PFT-specific fire parameters`); :math:`C_{m} =\sqrt{f_{m}}` and :math:`g(W)` represent the dependence of :math:`u_{p}` on fuel wetness and wind speed :math:`W`, respectively. :math:`g(W)` is derived from the mathematical properties of the ellipse and equation :eq:`23.16` and :eq:`23.17` .. math:: :label: 23.19 @@ -186,16 +189,24 @@ Since g(\ *W*)=1.0, and \ :math:`L_{B}` and :math:`H_{B}` are at their maxima \ g(0)=\frac{1+\frac{1}{H_{B} ^{\max } } }{2L_{B} ^{\max } } =0.05. -In the absence of globally gridded data on barriers to fire (e.g. rivers, lakes, roads, firebreaks) and human fire-fighting efforts, average fire duration is simply assumed equal to 1 which is the observed 2001–2004 mean persistence of most fires in the world (:ref:`Giglio et al. 2006 `). +Fire duration is affected by fire fighting capacity which depends on socioeconomic condition and by the natural vegetation fuel continuity: -As with the socioeconomic influence on fire occurrence, we assume that the socioeconomic influence on fire spreading is negligible in regions of :math:`D_{p} \le 0.1` person km\ :sup:`-2`, i.e., :math:`F_{se} = 1.0`. In regions of :math:`D_{p} >0.1` person km\ :sup:`-2`, we parameterize such socioeconomic influence as: + +.. math:: + :label: 23.201 + + \tau=\tau*F_{se}F_{c} + +where :math:`\tau*` represents the fire duration under conditions without anthropogenic suppression and landscape fragmentation, setting to 5 days for all natural vegetation PFTs; :math:`F_{se}` is the socioeconomic effect on fire spread area; :math:`F_{c}` is the fuel continuity factor. + +As with the socioeconomic influence on fire occurrence, we assume that the socioeconomic influence on fire duration is negligible in regions of :math:`D_{p} \le 0.1` person km\ :sup:`-2`, i.e., :math:`F_{se} = 1.0`. In regions of :math:`D_{p} >0.1` person km\ :sup:`-2`, we parameterize such socioeconomic influence as: .. math:: :label: 23.21 F_{se} =F_{d} F_{e} -where :math:`{F}_{d}` and :math:`{F}_{e}` are effects of the demographic and economic conditions on the average spread area of a fire, and are identified by maximizing the explained variability of the GFED3 burned area fraction with both socioeconomic indices in grid cells with various dominant vegetation types. For shrub and grass PFTs, the demographic impact factor is +where :math:`{F}_{d}` and :math:`{F}_{e}` are effects of the demographic and economic conditions. For shrub and grass PFTs, the demographic impact factor is .. math:: :label: 23.22 @@ -228,6 +239,16 @@ and Equations :eq:`23.22` - :eq:`23.25` reflect that more developed and more densely populated regions have a higher fire fighting capability. +The continuity factor is the fractional coverage (0 to 1) of natural vegetation (not including bare soil) in the grid cell (:math:`f_{natveg}`) + +.. math:: + :label: 23.251 + + F_{c} =f_{natveg} =1 - f_{urban} - f_{lake} - f_{cropland} - f_{baresoil} + +where :math:`f_{urban}`, :math:`f_{lake}`, :math:`f_{cropland}`, and :math:`f_{baresoil}` are factional coverage of urban, lake, cropland, and bare soil. + + .. _Fire impact: Fire impact @@ -240,7 +261,7 @@ In post-fire regions, we calculate PFT-level fire carbon emissions from biomass \phi _{j} =A_{b,j} \mathbf{C}_{j} \bullet \mathbf{CC}_{j} -where :math:`A_{b,j}` (km\ :sup:`2` \s\ :sup:`-1`) is burned area for the :math:`j`\ th PFT; **C**\ :sub:`j` =(:math:`C_{leaf}`, :math:`C_{stem}`, :math:`C_{root}`, :math:`C_{ts}`) is a vector with carbon density (g C km :sup:`-2`) for leaf, stem (live and dead stem), root (fine, live coarse and dead coarse root), and transfer and storage carbon pools as elements; :math:`\mathbf{CC}_{j}` = (:math:`\mathbf{CC}_{leaf}`, :math:`\mathbf{CC}_{stem}`, :math:`\mathbf{CC}_{root}`, :math:`\mathbf{CC}_{ts}`) is the corresponding combustion completeness factor vector (:numref:`Table PFT-specific combustion completeness and fire mortality factors`). Moreover, we assume that 50% and 28% of column-level litter and coarse woody debris are burned and the corresponding carbon is transferred to atmosphere. +where :math:`A_{b,j}` (km\ :sup:`2` \s\ :sup:`-1`) is burned area for the :math:`j`\ th PFT; **C**\ :sub:`j` =(:math:`C_{leaf}`, :math:`C_{stem}`, :math:`C_{root}`, :math:`C_{ts}`) is a vector with carbon density (g C km :sup:`-2`) for leaf, stem (live and dead stem), root (fine, live coarse and dead coarse root), and transfer and storage carbon pools as elements; :math:`\mathbf{CC}_{j}` = (:math:`\mathbf{CC}_{leaf}`, :math:`\mathbf{CC}_{stem}`, :math:`\mathbf{CC}_{root}`, :math:`\mathbf{CC}_{ts}`) is the corresponding combustion completeness factor vector (:numref:`Table PFT-specific fire parameters`). Moreover, we assume that 50% and 28% of column-level litter and coarse woody debris are burned and the corresponding carbon is transferred to atmosphere. Tissue mortality due to fire leads to carbon transfers in two ways. First, carbon from uncombusted leaf, live stem, dead stem, root, and transfer and storage pools :math:`\mathbf{C^{'} _{j1}} ={(C_{{leaf}} (1-CC_{{leaf}} ),C_{{livestem}} (1-CC_{{stem}} ),C_{{deadstem}} (1-CC_{{stem}} ),C_{{root}} (1-CC_{{root}} ),C_{{ts}} (1-CC_{{ts}} ))}_{j}` (g C km\ :sup:`-2`) is transferred to litter as @@ -249,14 +270,14 @@ Tissue mortality due to fire leads to carbon transfers in two ways. First, carbo \Psi _{j1} =\frac{A_{b,j} }{f_{j} A_{g} } \mathbf{C^{'} _{j1}} \bullet M_{j1} -where :math:`M_{j1} =(M_{{leaf}},M_{{livestem,1}},M_{{deadstem}},M_{{root}},M_{{ts}} )_{j}` is the corresponding mortality factor vector (:numref:`Table PFT-specific combustion completeness and fire mortality factors`). Second, carbon from uncombusted live stems is transferred to dead stems as: +where :math:`M_{j1} =(M_{{leaf}},M_{{livestem,1}},M_{{deadstem}},M_{{root}},M_{{ts}} )_{j}` is the corresponding mortality factor vector (:numref:`Table PFT-specific fire parameters`). Second, carbon from uncombusted live stems is transferred to dead stems as: .. math:: :label: 23.28 \Psi _{j2} =\frac{A_{b,j} }{f_{j} A_{g} } C_{livestem} (1-CC_{stem} )M_{livestem,2} -where :math:`M_{livestem,2}` is the corresponding mortality factor (:numref:`Table PFT-specific combustion completeness and fire mortality factors`). +where :math:`M_{livestem,2}` is the corresponding mortality factor (:numref:`Table PFT-specific fire parameters`). Fire nitrogen emissions and nitrogen transfers due to fire-induced mortality are calculated the same way as for carbon, using the same values for combustion completeness and mortality factors. With CLM's dynamic vegetation option enabled, the number of tree PFT individuals killed by fire per km\ :sup:`2` (individual km\ :sup:`-2` s\ :sup:`-1`) is given by @@ -265,7 +286,7 @@ Fire nitrogen emissions and nitrogen transfers due to fire-induced mortality are P_{disturb,j} =\frac{A_{b,j} }{f_{j} A_{g} } P_{j} \xi _{j} -where :math:`P_{j}` (individual km\ :sup:`-2`) is the population density for the :math:`j` th tree PFT and :math:`\xi _{j}` is the whole-plant mortality factor (:numref:`Table PFT-specific combustion completeness and fire mortality factors`). +where :math:`P_{j}` (individual km\ :sup:`-2`) is the population density for the :math:`j` th tree PFT and :math:`\xi _{j}` is the whole-plant mortality factor (:numref:`Table PFT-specific fire parameters`). .. _Agricultural fires: @@ -279,7 +300,7 @@ The burned area of cropland (km\ :sup:`2` s\ :sup:`-1`) is taken as :math:`{A}_{ A_{b} =a_{1} f_{se} f_{t} f_{crop} A_{g} -where :math:`a_{1}` (s\ :sup:`-1`) is a constant; :math:`f_{se}` represents the socioeconomic effect on fires; :math:`f_{t}` determines the seasonality of agricultural fires; :math:`f_{crop}` is the fractional coverage of cropland. :math:`a_{1}` \ = 1.6x10\ :sup:`-4` \hr\ :sup:`-1`\ is estimated using an inverse method, by matching 1997-2004 simulations to the analysis of :ref:`van der Werf et al. (2010) ` that shows the 2001-2009 average contribution of cropland fires is 4.7% of the total global burned area. +where :math:`a_{1}` (s\ :sup:`-1`) is a constant; :math:`f_{se}` represents the socioeconomic effect on fires; :math:`f_{t}` determines the seasonality of agricultural fires; :math:`f_{crop}` is the fractional coverage of cropland. :math:`a_{1}` \ = 0.34 \hr\ :sup:`-1`\ is estimated using an inverse method, by matching simulated global agricultural burned area to the GFED5 (:ref:`Chen et al. 2023 `) cropland burned area of 82 Mha yr\ :sup:`-1` for 2002−2020. The socioeconomic factor :math:`f_{se}` is given as follows: @@ -293,18 +314,18 @@ Here .. math:: :label: 23.32 - f_{d} =0.04+0.96\times \exp [-\pi (\frac{D_{p} }{350} )^{0.5} ] + f_{d} =0.2+0.8\times \exp (-\pi \frac{D_{p} }{400} ) and .. math:: :label: 23.33 - f_{e} =0.01+0.99\times \exp (-\pi \frac{GDP}{10} ) + f_{e} =0.05+0.95\times \exp (-\pi \frac{GDP}{20} ) -are the effects of population density and GDP on burned area, derived in a similar way to equation :eq:`23.32` and :eq:`23.33`. :math:`f_{t}` is set to 1 at the first time step during the climatological peak month for agricultural fires (:ref:`van der Werf et al. 2010 `); :math:`{f}_{t}` is set to 0 otherwise. Peak month in this dataset correlates with the month after harvesting or the month before planting. In CLM we use this dataset the same way whether the CROP option is active or not, without regard to the CROP option's simulated planting and harvesting dates. +are the effects of population density and GDP on burned area, derived in a similar way to equation :eq:`23.32` and :eq:`23.33`. :math:`f_{t}` is set to 1 at the first time step of the climatological peak month for GFED5 agricultural burned area and during the post-harvest and pre-planting period. -In the post-fire region, fire impact is parameterized similar to section :numref:`Fire impact` but with combustion completeness factors and tissue mortality factors for crop PFTs (:numref:`Table PFT-specific combustion completeness and fire mortality factors`). +In the post-fire region, fire impact is parameterized similar to section :numref:`Fire impact` but with combustion completeness factors and tissue mortality factors for crop PFTs (:numref:`Table PFT-specific fire parameters`). .. _Deforestation fires: @@ -320,12 +341,12 @@ CLM focuses on deforestation fires in tropical closed forests. Tropical closed f where :math:`b` (s\ :sup:`-1`) is a global constant; :math:`f_{lu}` (fraction) represents the effect of decreasing fractional coverage of tree PFTs derived from land use data; :math:`f_{cli,d}` (fraction) represents the effect of climate conditions on the burned area. -Constants :math:`b` and :math:`{f}_{lu}` are calibrated based on observations and reanalysis datasets in the Amazon rainforest (tropical closed forests within 15.5 °S :math:`\text{-}` 10.5 °N, 30.5 ° W :math:`\text{-}` 91 ° W). :math:`b` = 0.033 d\ :sup:`-1` and :math:`f_{lu}` is defined as +Constants :math:`b` and :math:`{f}_{lu}` are calibrated based on observations and reanalysis datasets in the Amazon rainforest (tropical closed forests within 15.5 °S :math:`\text{-}` 10.5 °N, 30.5 ° W :math:`\text{-}` 91 ° W). :math:`b` = 0.03 d\ :sup:`-1` and :math:`f_{lu}` is defined as .. math:: :label: 23.35 - f_{lu} = \max (0.0005,0.19D-0.001) + f_{lu} = 0.67 \min (0.01,D) + 0.001 where :math:`D` (yr\ :sup:`-1`) is the annual loss of tree cover based on CLM land use and land cover change data. @@ -334,13 +355,9 @@ The effect of climate on deforestation fires is parameterized as: .. math:: :label: 23.36 - \begin{array}{ll} - f_{cli,d} \quad = & \quad \max \left[0,\min (1,\frac{b_{2} -P_{60d} }{b_{2} } )\right]^{0.5} \times \\ - & \quad \max \left[0,\min (1,\frac{b_{3} -P_{10d} }{b_{3} } )\right]^{0.5} \times \\ - & \quad \max \left[0,\min (1,\frac{0.25-P}{0.25} )\right] - \end{array} + f_{cli,d} = \max [0,\min (1,1- \frac{P_{30d} }{b_{1} })] \max [0,\min (1,1- \frac{P}{0.25 } )] -where :math:`P` (mm d :sup:`-1`) is instantaneous precipitation, while :math:`P_{60d}` (mm d\ :sup:`-1`) and :math:`P_{10d}` (mm d :sup:`-1`) are 60-day and 10-day running means of precipitation, respectively; :math:`b_{2}` (mm d :sup:`-1`) and :math:`b_{3}` (mm d :sup:`-1`) are the grid-cell dependent thresholds of :math:`P_{60d}` and :math:`P_{10d}`; 0.25 mm d :sup:`-1` is the maximum precipitation rate for drizzle. :ref:`Le Page et al. (2010) ` analyzed the relationship between large-scale deforestation fire counts and precipitation during 2003 :math:`\text{-}`\ 2006 in southern Amazonia where tropical evergreen trees (BET Tropical) are dominant. Figure 2 in :ref:`Le Page et al. (2010) ` showed that fires generally occurred if both :math:`P_{60d}` and :math:`P_{10d}` were less than about 4.0 mm d :sup:`-1`, and fires occurred more frequently in a drier environment. Based on the 30-yr (1985 to 2004) precipitation data in :ref:`Qian et al. (2006) `. The climatological precipitation of dry months (P < 4.0 mm d :sup:`-1`) in a year over tropical deciduous tree (BDT Tropical) dominated regions is 46% of that over BET Tropical dominated regions, so we set the PFT-dependent thresholds of :math:`P_{60d}` and :math:`P_{10d}` as 4.0 mm d :sup:`-1` for BET Tropical and 1.8 mm d :sup:`-1` (= 4.0 mm d :sup:`-1` :math:`\times` 46%) for BDT Tropical, and :math:`b`\ :sub:`2` and :math:`b`\ :sub:`3` are the average of thresholds of BET Tropical and BDT Tropical weighted bytheir coverage. +where :math:`P` (mm d :sup:`-1`) is instantaneous precipitation, while :math:`P_{30d}` (mm d\ :sup:`-1`) is 30-day running means of precipitation; :math:`b_{1}` is grid-cell dependent thresholds of :math:`P_{30d}`; 0.25 mm d :sup:`-1` is the maximum precipitation rate for drizzle. :math:`b_{1}` is the average of thresholds of BET Tropical (0.5 mm d :sup:`-1`) and BDT Tropical ( 3.0 mm d :sup:`-1`) by their fractional coverage, where thresholds are derived based on GFED5 burned area and dry-season CRUJRA climatological precipitation for BET to BDT dominant regions in the Amazon rainforests. The post-fire area due to deforestation is not limited to land-type conversion regions. In the tree-reduced region, the maximum fire carbon emissions are assumed to be 80% of the total conversion flux. According to the fraction of conversion flux for tropical trees in the tree-reduced region (60%) assigned by CLM4-CN, to reach the maximum fire carbon emissions in a conversion region requires burning this region about twice when we set PFT-dependent combustion completeness factors to about 0.3 for stem [the mean of 0.2\ :math:`{-}`\ 0.4 used in :ref:`van der Werf et al. (2010) `. Therefore, when the burned area calculated from equation :eq:`23.36` is no more than twice the tree-reduced area, we assume no escaped fires outside the land-type conversion region, and the fire-related fraction of the total conversion flux is estimated as :math:`\frac{A_{b} /A_{g} }{2D}`. Otherwise, 80% of the total conversion flux is assumed to be fire carbon emissions, and the biomass combustion and vegetation mortality outside the tree-reduced regions with an area fraction of :math:`\frac{A_{b} }{A_{g} } -2D` are set as in section :numref:`Fire impact`. @@ -356,14 +373,14 @@ The burned area due to peat fires is given as :math:`{A}_{b}`: A_{b} = c \ f_{cli,p} f_{peat} A_{g} -where :math:`c` (s\ :sup:`-1`) is a constant; :math:`f_{cli,p}` represents the effect of climate on the burned area; and :math:`f_{peat}` is the fractional coverage of peatland in the grid cell. :math:`c` = 0.17 :math:`\times` 10 :sup:`-3` hr\ :sup:`-1` for tropical peat fires and :math:`c` = 0.9 :math:`\times` 10 :sup:`-5` hr :sup:`-1` for boreal peat fires are derived using an inverse method, by matching simulations to earlier studies: about 2.4 Mha peatland was burned over Indonesia in 1997 (:ref:`Page et al. 2002 `) and the average burned area of peat fires in Western Canada was 0.2 Mha yr :sup:`-1` for 1980-1999 (:ref:`Turetsky et al. 2004 `). +where :math:`c` (s\ :sup:`-1`) is a constant; :math:`f_{cli,p}` represents the effect of climate on the burned area; and :math:`f_{peat}` is the fractional coverage of peatland in the grid cell. :math:`c` = 0.75 :math:`\times` 10 :sup:`-4` hr\ :sup:`-1` for tropical peat fires and :math:`c` = 0.58 :math:`\times` 10 :sup:`-4` hr :sup:`-1` for boreal peat fires are derived using an inverse method, by matching simulations to earlier studies: about 0.5 Mha yr :sup:`-1` for Indonesia tropical peat fires based on GFED5 for 2002–2014 (:ref:`Chen et al., 2023 `) and the average burned area of peat fires in Western Canada was 0.2 Mha yr :sup:`-1` for 1980-1999 (:ref:`Turetsky et al. 2004 `). -For tropical peat fires, :math:`f_{cli,p}` is set as a function of long-term precipitation :math:`P_{60d}` : +For tropical peat fires, :math:`f_{cli,p}` is set as a function of long-term precipitation :math:`P_{30d}` : .. math:: :label: 23.38 - f_{cli,p} = \ max \left[0,\min \left(1,\frac{4-P_{60d} }{4} \right)\right]^{2} . + f_{cli,p} = \max \left[0,\min \left(1,1- \frac{P_{30d} }{6.5} \right)\right] . For boreal peat fires, :math:`f_{cli,p}` is set to @@ -389,46 +406,44 @@ Emissions for trace gas and aerosol species x and the j-th PFT, :math:`E_{x,j}` E_{x,j} = EF_{x,j}\frac{\phi _{j} }{[C]}. -Here, :math:`EF_{x,j}` (g species (g dm)\ :sup:`-1`) is PFT-dependent emission factor scaled from biome-level values (Li et al., in prep, also used for FireMIP fire emissions data) by Dr. Val Martin and Dr. Li. :math:`[C]` = 0.5 (g C (g dm)\ :sup:`-1`) is a conversion factor from dry matter to carbon. +Here, :math:`EF_{x,j}` (g species (g dm)\ :sup:`-1`) is PFT-dependent emission factor scaled from biome-level values (:ref:`Li et al. 2019 `; :ref:`Li et al. 2024b `) :math:`[C]` = 0.5 (g C (g dm)\ :sup:`-1`) is a conversion factor from dry matter to carbon. Emission height is PFT-dependent: 4.3 km for needleleaf tree PFTs, 3 km for other boreal and temperate tree PFTs, 2.5 km for tropical tree PFTs, 2 km for shrub PFTs, and 1 km for grass and crop PFTs. These values are compiled from earlier studies by Dr. Val Martin. -.. _Table PFT-specific combustion completeness and fire mortality factors: - -.. table:: PFT-specific combustion completeness and fire mortality factors. - - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | PFT | *CC*\ :sub:`leaf` | *CC*\ :sub:`stem` | *CC*\ :sub:`root` | *CC*\ :sub:`ts` | *M*\ :sub:`leaf` | *M*\ :sub:`livestem,1` | *M*\ :sub:`deadstem` | *M*\ :sub:`root` | *M*\ :sub:`ts` | *M*\ :sub:`livestem,2` | :math:`\xi`\ :sub:`j` | - +==================================+===========================+===========================+===========================+=========================+==========================+==============================+==============================+==========================+========================+==============================+=================================+ - | NET Temperate | 0.80 | 0.30 | 0.00 | 0.50 | 0.80 | 0.15 | 0.15 | 0.15 | 0.50 | 0.35 | 0.15 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | NET Boreal | 0.80 | 0.30 | 0.00 | 0.50 | 0.80 | 0.15 | 0.15 | 0.15 | 0.50 | 0.35 | 0.15 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | NDT Boreal | 0.80 | 0.30 | 0.00 | 0.50 | 0.80 | 0.15 | 0.15 | 0.15 | 0.50 | 0.35 | 0.15 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | BET Tropical | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.13 | 0.13 | 0.13 | 0.45 | 0.32 | 0.13 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | BET Temperate | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.13 | 0.13 | 0.13 | 0.45 | 0.32 | 0.13 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | BDT Tropical | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.10 | 0.10 | 0.10 | 0.35 | 0.25 | 0.10 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | BDT Temperate | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.10 | 0.10 | 0.10 | 0.35 | 0.25 | 0.10 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | BDT Boreal | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.13 | 0.13 | 0.13 | 0.45 | 0.32 | 0.13 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | BES Temperate | 0.80 | 0.35 | 0.00 | 0.55 | 0.80 | 0.17 | 0.17 | 0.17 | 0.55 | 0.38 | 0.17 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | BDS Temperate | 0.80 | 0.35 | 0.00 | 0.55 | 0.80 | 0.17 | 0.17 | 0.17 | 0.55 | 0.38 | 0.17 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | BDS Boreal | 0.80 | 0.35 | 0.00 | 0.55 | 0.80 | 0.17 | 0.17 | 0.17 | 0.55 | 0.38 | 0.17 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | C\ :sub:`3` Grass Arctic | 0.80 | 0.80 | 0.00 | 0.80 | 0.80 | 0.20 | 0.20 | 0.20 | 0.80 | 0.60 | 0.20 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | C\ :sub:`3` Grass | 0.80 | 0.80 | 0.00 | 0.80 | 0.80 | 0.20 | 0.20 | 0.20 | 0.80 | 0.60 | 0.20 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | C\ :sub:`4` Grass | 0.80 | 0.80 | 0.00 | 0.80 | 0.80 | 0.20 | 0.20 | 0.20 | 0.80 | 0.60 | 0.20 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - | Crop | 0.80 | 0.80 | 0.00 | 0.80 | 0.80 | 0.20 | 0.20 | 0.20 | 0.80 | 0.60 | 0.20 | - +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+ - -Leaves (:math:`CC_{leaf}` ), stems (:math:`CC_{stem}` ), roots (:math:`CC_{root}` ), and transfer and storage carbon (:math:`CC_{ts}` ); mortality factors for leaves (:math:`M_{leaf}` ), live stems (:math:`M_{livestem,1}` ), dead stems (:math:`M_{deadstem}` ), roots (:math:`M_{root}` ), and transfer and storage carbon (:math:`M_{ts}` ) related to the carbon transfers from these pools to litter pool; mortality factors for live stems (:math:`M_{livestem,2}` ) related to the carbon transfer from live stems to dead stems; whole-plant mortality factor (:math:`\xi _{j}` ). +.. _Table PFT-specific fire parameters: + +.. table:: PFT-specific fire parameters. + + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | PFT | *CC*\ :sub:`leaf` | *CC*\ :sub:`stem` | *CC*\ :sub:`root` | *CC*\ :sub:`ts` | *M*\ :sub:`leaf` | *M*\ :sub:`livestem,1` | *M*\ :sub:`deadstem` | *M*\ :sub:`root` | *M*\ :sub:`ts` | *M*\ :sub:`livestem,2` | :math:`\xi`\ :sub:`j` | :math:`u`\ :sub:`max` | :math:`\beta`\ :sub:`low` | :math:`\beta`\ :sub:`up` | + +==================================+===========================+===========================+===========================+=========================+==========================+==============================+==============================+==========================+========================+==============================+=================================+====================================+====================================+====================================+ + | NET Temperate | 0.80 | 0.30 | 0.00 | 0.50 | 0.80 | 0.15 | 0.15 | 0.15 | 0.50 | 0.35 | 0.15 | 0.020 | 0.25 | 0.55 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | NET Boreal | 0.80 | 0.30 | 0.00 | 0.50 | 0.80 | 0.15 | 0.15 | 0.15 | 0.50 | 0.35 | 0.15 | 0.023 | 0.35 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | NDT Boreal | 0.80 | 0.30 | 0.00 | 0.50 | 0.80 | 0.15 | 0.15 | 0.15 | 0.50 | 0.35 | 0.15 | 0.023 | 0.35 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | BET Tropical | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.13 | 0.13 | 0.13 | 0.45 | 0.32 | 0.13 | 0.053 | 0.35 | 0.75 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | BET Temperate | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.13 | 0.13 | 0.13 | 0.45 | 0.32 | 0.13 | 0.020 | 0.3 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | BDT Tropical | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.10 | 0.10 | 0.10 | 0.35 | 0.25 | 0.10 | 0.033 | 0.3 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | BDT Temperate | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.13 | 0.13 | 0.13 | 0.45 | 0.32 | 0.13 | 0.020 | 0.3 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | BDT Boreal | 0.80 | 0.27 | 0.00 | 0.45 | 0.80 | 0.13 | 0.13 | 0.13 | 0.45 | 0.32 | 0.13 | 0.020 | 0.3 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | BES Temperate | 0.80 | 0.35 | 0.00 | 0.55 | 0.80 | 0.17 | 0.17 | 0.17 | 0.55 | 0.38 | 0.17 | 0.020 | 0.3 | 0.55 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | BDS Temperate | 0.80 | 0.35 | 0.00 | 0.55 | 0.80 | 0.17 | 0.17 | 0.17 | 0.55 | 0.38 | 0.17 | 0.020 | 0.3 | 0.55 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | BDS Boreal | 0.80 | 0.35 | 0.00 | 0.55 | 0.80 | 0.17 | 0.17 | 0.17 | 0.55 | 0.38 | 0.17 | 0.023 | 0.35 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | C\ :sub:`3` Grass Arctic | 0.80 | 0.80 | 0.00 | 0.80 | 0.80 | 0.20 | 0.20 | 0.20 | 0.80 | 0.60 | 0.20 | 0.023 | 0.35 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | C\ :sub:`3` Grass | 0.80 | 0.80 | 0.00 | 0.80 | 0.80 | 0.20 | 0.20 | 0.20 | 0.80 | 0.60 | 0.20 | 0.048 | 0.3 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + | C\ :sub:`4` Grass | 0.80 | 0.80 | 0.00 | 0.80 | 0.80 | 0.20 | 0.20 | 0.20 | 0.80 | 0.60 | 0.20 | 0.062 | 0.4 | 0.7 | + +----------------------------------+---------------------------+---------------------------+---------------------------+-------------------------+--------------------------+------------------------------+------------------------------+--------------------------+------------------------+------------------------------+---------------------------------+------------------------------------+------------------------------------+------------------------------------+ + +Leaves (:math:`CC_{leaf}` ), stems (:math:`CC_{stem}` ), roots (:math:`CC_{root}` ), and transfer and storage carbon (:math:`CC_{ts}` ); mortality factors for maximum fire spread rate (:math:`u_{max}`), lower and upper thresholds for root-zone soil wetness (:math:`\beta _{low}` and :math:`\beta _{up}`), leaves (:math:`M_{leaf}` ), live stems (:math:`M_{livestem,1}` ), dead stems (:math:`M_{deadstem}` ), roots (:math:`M_{root}` ), and transfer and storage carbon (:math:`M_{ts}` ) related to the carbon transfers from these pools to litter pool; mortality factors for live stems (:math:`M_{livestem,2}` ) related to the carbon transfer from live stems to dead stems; whole-plant mortality factor (:math:`\xi _{j}` ). diff --git a/doc/source/tech_note/Introduction/CLM50_Tech_Note_Introduction.rst b/doc/source/tech_note/Introduction/CLM50_Tech_Note_Introduction.rst index 46a134485b..5925c29270 100644 --- a/doc/source/tech_note/Introduction/CLM50_Tech_Note_Introduction.rst +++ b/doc/source/tech_note/Introduction/CLM50_Tech_Note_Introduction.rst @@ -125,7 +125,7 @@ P. O. Box 3000, Boulder, Colorado 80307-300 - :numref:`Table Respiration fractions for Century-based structure` Respiration fractions for litter and SOM pools for Century-based structure -- :numref:`Table PFT-specific combustion completeness and fire mortality factors` PFT-specific combustion completeness and fire mortality factors. +- :numref:`Table PFT-specific fire parameters` PFT-specific fire parameters. - :numref:`Table Methane Parameter descriptions` Parameter descriptions and sensitivity analysis ranges applied in the methane model. diff --git a/doc/source/tech_note/References/CLM50_Tech_Note_References.rst b/doc/source/tech_note/References/CLM50_Tech_Note_References.rst index e5191e247c..e692e4ee1b 100644 --- a/doc/source/tech_note/References/CLM50_Tech_Note_References.rst +++ b/doc/source/tech_note/References/CLM50_Tech_Note_References.rst @@ -220,6 +220,10 @@ Castillo, G., Kendra, C., Levis, S., and Thornton, P. 2012. Evaluation of the ne Cao, M., Marshall, S. and Gregson, K., 1996. Global carbon exchange and methane emissions from natural wetlands: Application of a process-based model. J. Geophys. Res. 101(D9):14,399-14,414. +.. _Chenetal2023: + +Chen, Y., Hall, J., van Wees, D., Andela, N., Hantson, S., Giglio, L., van der Werf, G.R., Morton, D.C., Randerson, J.T. 2023. Multi-decadal trends and variability in burned area from the fifth version of the Global Fire Emissions Database (GFED5). Earth Syst. Sci. Data 15:5227-5259. + .. _Chengetal2019: Cheng, Y. et al., 2019. Parameterizing perennial bioenergy crops in Version 5 of the Community Land Model Based on Site‐Level Observations in the Central Midwestern United States. Journal of Advances in Modeling Earth Systems, 2(2013), 1–24. https://doi.org/10.1029/2019MS001719 @@ -504,10 +508,6 @@ Ghimire, B., W. J. Riley, C. D. Koven, M. Mu, and J. T. Randerson, 2016: Represe Gholz, H.L., Perry, C.S., Cropper, W.P., Jr. and Hendry, L.C., 1985. Litterfall, decomposition, and nitrogen and phosphorous dynamics in a chronosequence of slash pine (*Pinus elliottii*) plantations. Forest Science, 31: 463-478. -.. _Giglioetal2006: - -Giglio, L., Csiszar, I., and Justice, C.O. 2006. Global distribution and seasonality of active fires as observed with the Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. J. Geophys. Res. 111:G02016. DOI:10.1029/2005JG000142. - .. _GlobalSoilDataTask2000: Global Soil Data Task 2000. Global soil data products CD-ROM (IGBP-DIS). International Geosphere-Biosphere Programme-Data and Information Available Services [Available online at http://www.daac.ornl.gov]. @@ -824,10 +824,6 @@ Lee, H., Swenson, S.C., Slater A.G. and Lawrence D.M., 2014. Effects of excess g Lehner, B., Verdin, K. and Jarvis, A., 2008. New global hydrograhy derived from spaceborne elevation data. Eos Trans., AGU, 89, 93 – 94. -.. _LePageetal2010: - -Le Page, Y., van der Werf, G.R., Morton, D.C., and Pereira, J.M.C. 2010. Modeling fire-driven deforestation potential in Amazonia under current and projected climate conditions. J. Geophys. Res. 115:G03012. DOI:10.1029/2009JG001190. - .. _Lerman1979: Lerman, A., 1979. Geochemical processes: Water and sediment environments. John Wiley and Sons, New York, N.Y. @@ -880,6 +876,14 @@ Li, F., Zeng, X. D., and Levis, S. 2012b. Corrigendum to "A process-based fire p Li, F., Levis, S., and Ward, D. S. 2013a. Quantifying the role of fire in the Earth system – Part 1: Improved global fire modeling in the Community Earth System Model (CESM1). Biogeosciences 10:2293-2314. +.. _Lietal2019: + +Li, F., Val Martin, M., Andreae, M.O., Arneth, A., Hantson, S., Kaiser, J.W., Lasslop, G., Yue, C., Bachelet, D., Forrest, M., Kluzek, E., Liu, X., Mangeon, S., Melton, J.R., Ward, D.S., Darmenov, A., Hickler, T., Ichoku, C., Magi, B.I., Sitch, S., van der Werf, G.R., Wiedinmyer, C., Rabin, S.S. 2019. Historical (1700-2012) global multi-model estimates of the fire emissions from the Fire Modeling Intercomparison Project (FireMIP). Atmos. Chem. Phys. 19:12545-12567. + +.. _Lietal2024b: + +Li, F. et al. 2024. Quantifying the role of fire in the Earth system: Improved global fire modeling in Earth system models. AGU Fall Meeting 2024, Washington, D.C., USA, 9-13 December 2024, GC41E-01. https://agu.confex.com/agu/agu24/meetingapp.cgi/Paper/1529786. + .. _LiLawrence2017: Li, F., and Lawrence, D. 2017. Role of fire in the global land water budget during the 20th century through changing ecosystems. J. Clim. 30: 1894-1908. @@ -900,7 +904,7 @@ Li, H., L. Leung, A. Getirana, M. Huang, H. Wu, Y. Xu, J. Guo and N. Voisin. 201 Li, H., L. Leung, T. Tesfa, N. Voisin, M. Hejazi, L. Liu, Y. Liu, J. Rice, H. Wu, and X. Yang. 2015. Modeling stream temperature in the Anthropocene: An earth system modeling approach, J. Adv. Model. Earth Syst., 7, doi:10.1002/2015MS000471. -.. _Lietal2024: +.. _Lietal2024a: Li, X. "C", Zhao, L., Oleson, K., Zhou, Y., Qin, Y., Zhang, K., and Fang, B. 2024. Enhancing urban climate‐energy modeling in the Community Earth System Model (CESM) through explicit representation of urban air‐conditioning adoption. JAMES, 16, e2023MS004107. https://doi.org/10.1029/2023MS004107. diff --git a/doc/source/tech_note/Urban/CLM50_Tech_Note_Urban.rst b/doc/source/tech_note/Urban/CLM50_Tech_Note_Urban.rst index 695281556f..e352d1a9e6 100644 --- a/doc/source/tech_note/Urban/CLM50_Tech_Note_Urban.rst +++ b/doc/source/tech_note/Urban/CLM50_Tech_Note_Urban.rst @@ -21,7 +21,7 @@ The main changes in the urban model from CLM5.0 to CLM6.0 are (see below) 1) an The building energy model introduced in :ref:`Oleson and Feddema (2020) ` accounts for the conduction of heat through interior surfaces (roof, sunlit and shaded walls, and floors), convection (sensible heat exchange) between interior surfaces and building air, longwave radiation exchange between interior surfaces, and ventilation (natural infiltration and exfiltration). Idealized HAC systems are assumed where the system capacity is infinite and the system supplies the amount of energy needed to keep the indoor air temperature (:math:`T_{iB}`) within maximum and minimum emperatures (:math:`T_{iB,\, \max },\, T_{iB,\, \min }` ), thus explicitly resolving space heating and AC fluxes. Anthropogenic sources of waste heat (:math:`Q_{H,\, waste}` ) from HAC that account for inefficiencies in the heating and AC equipment and from energy lost in the conversion of primary energy sources to end use energy are derived from :ref:`Sivak (2013) `. These sources of waste heat are incorporated as modifications to the canyon energy budget. -An explicit AC adoption parameterization for the BEM was developed for CLM6.0 (:ref:`Li et al. (2024) `). An AC adoption parameter is introduced (:math:`p_{AC}` ). The AC flux is first calculated under saturated AC adoption (i.e., :math:`p_{AC}=100%` ). The actual AC flux removed from the indoor air is then scaled based on :math:`p_{AC}` and the waste heat added to the urban canyon due to AC energy use is also scaled by :math:`p_{AC}`. A global, spatially explicit dataset for the AC adoption rate was developed at country- and sub-country-level from sources such as the International Energy Agency (IEA), national surveys, scientific literature, and others. For use with CLM, the AC adoption parameter was regridded to 0.9° latitude by 1.25° longitude and is read in for each of the three urban density classes using the file specified by the ``urbantv_streams`` namelist group (variables ``p_ac_MD``, ``p_ac_HD``, ``p_ac_TBD``). The maximum building interior temperature is also specified by the file in the ``urbantv_streams`` namelist group and is now considered to be the AC proxy setpoint in the parameterization and is set to 300K for all urban density classes (variables ``tbuildmax_MD``', ``tbuildmax_HD``, ``tbuildmax_TBD``). The explicit AC adoption parameterization in combination with the AC adoption rate dataset significantly improve CLM's performance in model building AC energy flux, both in magnitude and spatial variability (:ref:`Li et al. (2024) `). +An explicit AC adoption parameterization for the BEM was developed for CLM6.0 (:ref:`Li et al. (2024) `). An AC adoption parameter is introduced (:math:`p_{AC}` ). The AC flux is first calculated under saturated AC adoption (i.e., :math:`p_{AC}=100%` ). The actual AC flux removed from the indoor air is then scaled based on :math:`p_{AC}` and the waste heat added to the urban canyon due to AC energy use is also scaled by :math:`p_{AC}`. A global, spatially explicit dataset for the AC adoption rate was developed at country- and sub-country-level from sources such as the International Energy Agency (IEA), national surveys, scientific literature, and others. For use with CLM, the AC adoption parameter was regridded to 0.9° latitude by 1.25° longitude and is read in for each of the three urban density classes using the file specified by the ``urbantv_streams`` namelist group (variables ``p_ac_MD``, ``p_ac_HD``, ``p_ac_TBD``). The maximum building interior temperature is also specified by the file in the ``urbantv_streams`` namelist group and is now considered to be the AC proxy setpoint in the parameterization and is set to 300K for all urban density classes (variables ``tbuildmax_MD``', ``tbuildmax_HD``, ``tbuildmax_TBD``). The explicit AC adoption parameterization in combination with the AC adoption rate dataset significantly improve CLM's performance in model building AC energy flux, both in magnitude and spatial variability (:ref:`Li et al. (2024) `). Global urban properties were originally developed by :ref:`Jackson et al. (2010) `. For each of 33 distinct regions across the globe and four urban density classes [tall building district (TBD), and high, medium, and low density (HD, MD, LD)], thermal (e.g., heat capacity and thermal conductivity), radiative (e.g., albedo and emissivity) and morphological (e.g., height to width ratio, roof fraction, average building height, and pervious fraction of the canyon floor) properties, are provided for each of the density classes. Building interior minimum and maximum temperatures are prescribed based on climate and socioeconomic considerations. As described in :ref:`Oleson and Feddema (2020) ` the urban properties dataset in :ref:`Jackson et al. (2010) ` was modified with respect to wall and roof thermal properties to correct for biases in heat transfer due to layer and building type averaging. Further changes to the dataset reflect the need for scenario development, thus allowing for the creation of hypothetical wall types, and the easier interchange of wall facets. This slightly modified dataset was an option in CLM5.0.