Meaning of the output variables regarding U tendency of gravity drag

[wmingch@uw_edu]

Dear all,When I analyze the output data of WACCM5, I am confused with some output variables regaridng the gravity wave drag. For example, the long_name of BUTEND1 is U tendency c < -40, and another variable UTEND1 has the same long name (U tendency c < -40). What is the difference for the two variables?Besides, for the variable UTGWSPEC (long name is U tendency-gravity wave spectrum), what gravity wave it included (e.g. stationary waves generated by orography, convectoin and fonts)?  it will be great help if someone could give me some hints. Thanks in advance for kind help.Best,Mingcheng 

 

[jrichter@ucar_edu]

There are three gravity wave sources in WACCM5: orographic, convective, and frontal. The orographic GW tendency is UTGWORO (in the zonal direction). The total GW tendency from convective GWs is BUTGWSPEC and UTGWSPEC is from frontal waves. These two tendencies are broken down by phase speed range, so BUTEND1, BUTEND2, etc refer to the convective GWs with a given range of phase speeds (ie.: c < -40 m/s), etc; And UTEND1, UTEND2 are the same but for frontal waves.
Hope this helps,
Yaga