Changes between Version 18 and Version 19 of DevelopmentActivities/CMIP6/DevelopmentsCMIP6/zo_evaporation

Timestamp:

2016-03-21T18:04:37+01:00 (8 years ago)

Author:

nvuilsce

Comment:

--

DevelopmentActivities/CMIP6/DevelopmentsCMIP6/zo_evaporation

@@ -216 +216 @@
 With different values for z0,,m,, and z0,,h,,, it is a bit more complicated.
 When Fuxing and I, we worked with the formula z0,,h,,=z0,,m,,/10, we still used the calculation of cd with a single z0 (z0,,m,,) to get the mean z0,,m,, over the grid cell  (in condveg). And then we were assuming that z0,,h,mean,,=z0,,m,mean,,/10.
-But with those values of z0,,m,mean,, and z0,,h,mean,,, the mean drag coefficient over the pixel is not correct:(von_karman*LN(z,,ref,,/z0,,m,mean,,))*(von_karman*LN(z,,ref,,/z0,,h,mean,,)) != cd,,mean,,
+But with those values of z0,,m,mean,, and z0,,h,mean,,, the mean drag coefficient over the pixel is not correct:[[BR]]
+(von_karman*LN(z,,ref,,/z0,,m,mean,,))*(von_karman*LN(z,,ref,,/z0,,h,mean,,)) != cd,,mean,,
 
 When implementing the formulation of Su, I used two calculations of cd: one with only z0,,m,, to get the mean z0,,m,, over the grid cell, and one with only z0,,h,, to get the mean z0,,h,,. With these values of z0,,m,mean,, and z0,,h,mean,,, the value of the mean cd is well approximated. For formulas in which z0,,h,, is a fixed fraction of z0,,m,,, it is a better approximation than assuming that z0,,h,mean,,=z0,,m,mean,,/10.