On the Ecology of Mountainous Forests in a Changing Climate: A ...
On the Ecology of Mountainous Forests in a Changing Climate: A ...
On the Ecology of Mountainous Forests in a Changing Climate: A ...
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The forest model FORCLIM 87<br />
3.4.3 FORCLIM-E<br />
The generation <strong>of</strong> wea<strong>the</strong>r data <strong>in</strong> FORCLIM-E does not require any parameters besides<br />
<strong>the</strong> site-specific climatic data given <strong>in</strong> Appendix III. The m<strong>in</strong>imum w<strong>in</strong>ter temperature is<br />
directly calculated from <strong>the</strong> wea<strong>the</strong>r data and does not require any model parameters<br />
ei<strong>the</strong>r. The two parameters required for calculat<strong>in</strong>g <strong>the</strong> annual sum <strong>of</strong> degree-days are<br />
given <strong>in</strong> Tab. 3.16.<br />
Tab. 3.16: Default parameter values <strong>in</strong> <strong>the</strong> FORCLIM-E model.<br />
Parameter Description Value Unit Reference<br />
kDTT development threshold 5.5 °C Botk<strong>in</strong> et al. (1972a)<br />
kDays average length <strong>of</strong> months 30.5 d –<br />
kSlAsp slope & aspect parameter 0 – –<br />
kFC soil field capacity 30.0 cm Richard et al. (1978)<br />
Tab. 3.17: Results from <strong>the</strong> l<strong>in</strong>ear regression analysis <strong>of</strong> <strong>the</strong> parameter kLatPtr aga<strong>in</strong>st latitude (kLat,<br />
Eq. 3.76). Raw data from Pastor & Post (1985).<br />
Month a b r 2<br />
Jan 1.1226 -7.31·10 -3 0.977<br />
Feb 0.9859 -3.87·10 -3 0.987<br />
Mar 1.0454 -4.92·10 -4 0.640<br />
Apr 0.9708 3.52·10 -3 0.988<br />
May 0.9605 7.15·10 -3 0.988<br />
Jun 0.9185 8.47·10 -3 0.990<br />
Jul 0.9669 7.64·10 -3 0.986<br />
Aug 0.9892 4.94·10 -3 0.981<br />
Sep 0.9900 1.20·10 -3 0.860<br />
Oct 1.0600 -2.63·10 -3 0.957<br />
Nov 1.0815 -6.37·10 -3 0.987<br />
Dec 1.1444 -8.66·10 -3 0.982<br />
The parameters <strong>of</strong> <strong>the</strong> soil moisture balance model are fully documented <strong>in</strong> Thornthwaite<br />
& Ma<strong>the</strong>r (1957) and Pastor & Post (1984, 1985); <strong>the</strong>y are used <strong>in</strong> <strong>the</strong> FORCLIM-E<br />
model with a few exceptions: First, <strong>the</strong> default values <strong>of</strong> <strong>the</strong> site-specific slope/aspect<br />
parameter (kSlAsp) and <strong>of</strong> <strong>the</strong> soil field capacity, which is site-specific as well, are listed<br />
<strong>in</strong> Tab. 3.16. Second, <strong>the</strong> parameters required to correct <strong>the</strong> potential monthly evapotranspiration<br />
accord<strong>in</strong>g to geographical latitude and sun angle (kLatPtr) are given <strong>in</strong><br />
Pastor & Post (1985, pp. 113f.) as one large data matrix. Equations <strong>of</strong> <strong>the</strong> form<br />
kLatPtr = a + b·kLat (3.76)