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| 2 | #include "snag.h"
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2 | #include "snag.h"
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| 3 | #include "tree.h"
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3 | #include "tree.h"
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| 4 | #include "species.h"
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4 | #include "species.h"
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| 5 | #include "globalsettings.h"
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5 | #include "globalsettings.h"
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| 6 | #include "expression.h"
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6 | #include "expression.h"
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| - | 7 | // for calculation of climate decomposition
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| - | 8 | #include "resourceunit.h"
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| - | 9 | #include "watercycle.h"
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| - | 10 | #include "climate.h"
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| 7 | 11 | ||
| 8 | /** @class Snag
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12 | /** @class Snag
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| 9 | Snag deals with carbon / nitrogen fluxes from the forest until the reach soil pools.
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13 | Snag deals with carbon / nitrogen fluxes from the forest until the reach soil pools.
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| 10 | Snag lives on the level of |
14 | Snag lives on the level of the ResourceUnit; carbon fluxes from trees enter Snag, and parts of the biomass of snags
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| 11 | is subsequently forwarded to the soil sub model.
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15 | is subsequently forwarded to the soil sub model.
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| 12 | 16 | ||
| 13 | */
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17 | */
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| 14 | // static variables
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18 | // static variables
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| 15 | double Snag::mDBHLower = 10.; |
19 | double Snag::mDBHLower = 10.; |
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| 30 | } soilparams; |
34 | } soilparams; |
| 31 | 35 | ||
| 32 | 36 | ||
| 33 | Snag::Snag() |
37 | Snag::Snag() |
| 34 | {
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38 | {
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| - | 39 | mRU = 0; |
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| 35 | soilparams.pDWDformula.setExpression("1-1/(1+exp(-6.78+0.262*tsd))"); |
40 | soilparams.pDWDformula.setExpression("1-1/(1+exp(-6.78+0.262*tsd))"); |
| 36 | CNPool::setCFraction(biomassCFraction); |
41 | CNPool::setCFraction(biomassCFraction); |
| 37 | }
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42 | }
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| 38 | 43 | ||
| 39 | void Snag::setup() |
44 | void Snag::setup( const ResourceUnit *ru) |
| 40 | {
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45 | {
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| - | 46 | mRU = ru; |
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| - | 47 | mClimateFactor = 0.; |
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| 41 | // branches
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48 | // branches
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| 42 | mBranchCounter=0; |
49 | mBranchCounter=0; |
| 43 | for (int i=0;i<3;i++) { |
50 | for (int i=0;i<3;i++) { |
| 44 | mTimeSinceDeath[i] = 0.; |
51 | mTimeSinceDeath[i] = 0.; |
| 45 | mNumberOfSnags[i] = 0.; |
52 | mNumberOfSnags[i] = 0.; |
| Line 82... | Line 89... | ||
| 82 | mRefractoryFlux.clear(); |
89 | mRefractoryFlux.clear(); |
| 83 | mTotalToAtm.clear(); |
90 | mTotalToAtm.clear(); |
| 84 | mTotalToExtern.clear(); |
91 | mTotalToExtern.clear(); |
| 85 | mTotalIn.clear(); |
92 | mTotalIn.clear(); |
| 86 | mSWDtoSoil.clear(); |
93 | mSWDtoSoil.clear(); |
| - | 94 | }
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| - | 95 | ||
| - | 96 | /// calculate the dynamic climate modifier for decomposition 're'
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| - | 97 | double Snag::calculateClimateFactors() |
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| - | 98 | {
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| - | 99 | double rel_wc; |
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| - | 100 | double ft, fw; |
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| - | 101 | double f_sum = 0.; |
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| - | 102 | for (const ClimateDay *day=mRU->climate()->begin(); day!=mRU->climate()->end(); ++day) |
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| - | 103 | {
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| - | 104 | rel_wc = mRU->waterCycle()->relContent(day->day); // relative water content (0..1) of the day |
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| - | 105 | ft = exp(308.56*(1./56.02-1./((273.+day->temperature)-227.13))); // empirical variable Q10 model of Lloyd and Taylor (1994), see also Adair et al. (2008) |
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| - | 106 | fw = pow(1.-exp(-0.2*rel_wc),5.); // # see Standcarb for the 'stable soil' pool |
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| - | 107 | f_sum += ft*fw; |
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| - | 108 | }
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| - | 109 | // the climate factor is defined as the arithmentic annual mean value
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| - | 110 | mClimateFactor = f_sum / double(mRU->climate()->daysOfYear()); |
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| - | 111 | return mClimateFactor; |
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| 87 | }
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112 | }
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| 88 | 113 | ||
| 89 | // do the yearly calculation
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114 | // do the yearly calculation
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| 90 | // see http://iland.boku.ac.at/snag+dynamics
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115 | // see http://iland.boku.ac.at/snag+dynamics
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| 91 | void Snag::processYear() |
116 | void Snag::processYear() |
| Line 102... | Line 127... | ||
| 102 | 127 | ||
| 103 | mSWDtoSoil.clear(); |
128 | mSWDtoSoil.clear(); |
| 104 | // process standing snags.
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129 | // process standing snags.
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| 105 | // the input of the current year is in the mToSWD-Pools
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130 | // the input of the current year is in the mToSWD-Pools
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| 106 | double tsd; |
131 | double tsd; |
| 107 | const double climate_factor_re = |
132 | const double climate_factor_re = calculateClimateFactors(); |
| 108 | for (int i=0;i<3;i++) { |
133 | for (int i=0;i<3;i++) { |
| 109 | // calculate 'tsd', i.e. time-since-death (see SnagDecay.xls for calculation details)
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134 | // calculate 'tsd', i.e. time-since-death (see SnagDecay.xls for calculation details)
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| 110 | // time_since_death = tsd_last_year*state_before / (state_before+input) + 1
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135 | // time_since_death = tsd_last_year*state_before / (state_before+input) + 1
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| 111 | if (mSWD[i].C>0.) |
136 | if (mSWD[i].C>0.) |
| 112 | tsd = mTimeSinceDeath[i]*mSWD[i].C / (mSWD[i].C+mToSWD[i].C) + 1.; |
137 | tsd = mTimeSinceDeath[i]*mSWD[i].C / (mSWD[i].C+mToSWD[i].C) + 1.; |