From 1cab6a0d8e84285496ab8deb235885446fb183e4 Mon Sep 17 00:00:00 2001 From: Jessica Meixner Date: Mon, 1 Nov 2021 14:14:11 +0000 Subject: [PATCH] update to protect a divide by zero in ST4 --- model/src/w3src4md.F90 | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/model/src/w3src4md.F90 b/model/src/w3src4md.F90 index bd35e07f8..ae5a21a3c 100644 --- a/model/src/w3src4md.F90 +++ b/model/src/w3src4md.F90 @@ -1647,13 +1647,19 @@ SUBROUTINE CALC_USTAR(WINDSPEED,TAUW,USTAR,Z0,CHARN) ! ! Determines roughness length ! - SQRTCDM1 = MIN(WINDSPEED/USTAR,100.0) - Z0 = ZZWND*EXP(-KAPPA*SQRTCDM1) IF (USTAR.GT.0.001) THEN + SQRTCDM1 = MIN(WINDSPEED/USTAR,100.0) + Z0 = ZZWND*EXP(-KAPPA*SQRTCDM1) CHARN = GRAV*Z0/USTAR**2 ELSE + IF (USTAR.GT.0) THEN + SQRTCDM1 = MIN(WINDSPEED/USTAR,100.0) + Z0 = ZZWND*EXP(-KAPPA*SQRTCDM1) + ELSE + Z0 = AALPHA*0.001*0.001/GRAV + END IF CHARN = AALPHA - END IF + END IF ! RETURN END SUBROUTINE CALC_USTAR