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程式修改及編譯

Table of contents

背景

基本上obsgrid程式也是個內插程式，是需要給定搜索半徑等條件的。程式執行會因為解析度的變化而異，會需要修改編譯。

程式下載、率定、編譯

下載、設定

  • git clone https://github.com/wrf-model/OBSGRID.git，會在工作目錄下產生OBSGRID的新目錄，並將github上的原始碼下載到本機。
  • csh進入c shell 環境
  • 設定環境變數
    • setenv NETCDF /usr/local/Cellar/netcdf/4.8.1
    • setenv HDF5 /usr/local/Cellar/hdf5/1.12.1
    • setenv JASPERLIB /usr/local/Cellar/jasper/2.0.33/lib
    • setenv JASPERINC /usr/local/Cellar/jasper/2.0.33/include
    • setenv WRF_DIR /Users/WRF4.3
  • 執行configure選擇恰當的編譯方式
  • 執行compile進行編譯
  • 詳見README

gfortran與ifort選項的差異

$ diff configure.oa_GNU configure.oa_ifort
26a27,28
> NETCDF          =       /opt/netcdf/netcdf4_intel
>
36c38
< # Settings for Darwin - with g95 compiler
---
> # Settings for PC Linux i486 i586 i686 x86_64, Intel compiler
38,48c40,48
< FC            =       gfortran
< FFLAGS                =       -O3 -ffree-form -fconvert=big-endian #-fallow-argument-mismatch
< F77FLAGS      =       -O3 -ffixed-form -fconvert=big-endian #-fallow-argument-mismatch
< FNGFLAGS      =       $(FFLAGS)
< LDFLAGS               =       -Wl,-stack_size,20000000,-stack_addr,0xc0000000
< CC            =       clang
< CFLAGS                =
< CPP           =       /usr/bin/cpp
< CPPFLAGS      =       -C -P -traditional
< RANLIB                =
< LOCAL_LIBS    =       -L/usr/X11R6/lib -lX11
---
> FC            =       ifort
> FFLAGS                =       -FR -convert big_endian
> F77FLAGS      =       -convert big_endian
> FNGFLAGS      =       $(FFLAGS)
> LDFLAGS               =
> CC            =       gcc
> CFLAGS                =       -w
> CPP           =       /opt/intel_f/compilers_and_libraries_2020.0.166/linux/bin/intel64/fpp #/lib/cpp
> CPPFLAGS      =       -I. -C -P -DDEC -traditional

修改src/qc0_module.F90

修改緣由

  • 該程式會計算在測站附近的所有觀測點數，原程式是以250及網格距離的比例來計算box，
  • 如果網格間距太小，box會很大，將會有太多的觀測點納入，
  • 除了計算會非常沒有效率之外，還可能超過設定之最大觀測站點數而報錯。
SUBROUTINE ob_density ( xob , yob , grid_dist , numobs , tobbox , iew , jns )

!  Compute a guess at the observation density for the surface FDDA.

   IMPLICIT NONE

   REAL    , DIMENSION ( : )      :: xob, yob 
   REAL                           :: grid_dist
   INTEGER                        :: numobs
   REAL    , DIMENSION ( : , : )  :: tobbox
   INTEGER                        :: iew, jns 

   INTEGER                        :: num, iob, job, i, j , & 
                                     iobs , iobe , jobs , jobe
   REAL                           :: dist
    

   !  Loop through each of the station locations (numobs).  

   DO num = 1, numobs

      iob       = xob (num) 
      job       = yob (num)
      jobs = MAX ( job - NINT( 250. / grid_dist ) - 1 ,   1   )   
      jobe = MIN ( job + NINT( 250. / grid_dist ) + 1 , jns-1 )
      iobs = MAX ( iob - NINT( 250. / grid_dist ) - 1 ,   1   )   
      iobe = MIN ( iob + NINT( 250. / grid_dist ) + 1 , iew-1 )
      DO j = jobs , jobe
         DO i = iobs , iobe
            dist = SQRT ( ( REAL(i) - xob(num) ) **2 + ( REAL(j) - yob(num) ) **2 ) 
            IF ( dist .LT. 250. / grid_dist ) THEN
               tobbox(j,i) = tobbox(j,i) + 1 
            END IF
         END DO
      END DO

   END DO

END SUBROUTINE ob_density

各層網格之修改值

此處進行修改：

  • d1: 250.(不變)
  • d2: 54.
  • d3: 20.
  • d4: 6.

編譯腳本

kuang@114-32-164-198 /Users/WRF4.1/OBSGRID
$ cat mk.cs
for d in {1..4};do
  rm src/*.o src/*.mod
  rm -f src/qc0_module.F90
  cp src/qc0_module.F90.d$d src/qc0_module.F90
  compile 
  cp src/obsgrid.exe src/obsgrid$d.exe
done

Reference

  • Brian Reen, A Brief Guide to Observation Nudging in WRF, github,February 2016.
  • kkeene44, WRF Objective Analysis Program, github,12 Oct 2018.