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The official repository for the Weather Research and Forecasting (WRF) model
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Bug in "noahmplsm" when domain covers northern and southern hemisphere #707

Open ghost opened 5 years ago

ghost commented 5 years ago

It seems that a bug may be present in noahmplsm when the model domain covers the northern and southern hemisphere. In subroutine phenology, in case e.g. dveg=4 (default value), the day is shifted by half a year causing strong temperature gradients at the equator because the GREENFRAC and LAI fields suddenly change.

dudhia commented 5 years ago

I have seen this before and one of the other dveg options works better.It is a seasonally varying landuse at the equator which is not good for that option.This happened in East Africa,Jimy

On Tuesday, November 20, 2018, 7:06:40 PM GMT+8, thomasedds <notifications@github.com> wrote:

It seems that a bug may be present in noahmplsm when the model domain covers the northern and southern hemisphere. In subroutine phenology, in case e.g. dveg=4 (default value), the day is shifted by half a year causing strong temperature gradients at the equator because the GREENFRAC and LAI fields suddenly change.

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davegill commented 5 years ago

@barlage @weiwangncar

barlage commented 5 years ago

I'll repeat what Jimy said in that this is a known "issue" and the preferred solution is to use one of the satellite-based LAI options, i.e., dveg = 7,8,9 (my preference is 9). The reason this occurs is that when using the table-based options, there is only one phenology and it is generally based on mid-latitude vegetation. An additional option is for users to modify the table values to those appropriate for local vegetation phenology.

davegill commented 5 years ago

@dudhia @barlage @weiwangncar Folks, To protect the user, should we:

  1. Change the default dveg?
  2. Put in a check_a_mundo test for grid cells near the equator if ( NoahMP is used AND dveg==4 )?

This would not be identified as a "bug fix" per se, so we have time to formulate a good solution.