The link between the atmosphere and the ocean consists of thermal and momentum fluxes across the air/sea interface. For numerical models these fluxes are calculated based on long and short wave radiation, air temperature, sea surface temperature, wind, vapor pressure, and precipitation. This lab will give you a feel for the the spatial and temporal variability of three atmospheric variables and momentum, latent and net heat fluxes.
The data were retrieved from the Naval Operational Global Atmospheric Prediction System (NOGAPS), covering Julian day 32 to 77 of 1994 over 5-25N and 95-125E - the South China Sea. The atmospheric variables included are; air temperature, vapor pressure, and surface winds at 0000 GMT. Note: 0000GMT for the winter days covered here are before sunrise - the heat flux will not include solar/short wave radiation
This lab will use five Matlab scripts described below. By creating links to your working directory, to be called surflx.lab, these tools will be made accessible to you. The link file to run is /data/span13/mv4030/link_surflx.
run_Tmov -> displays 46 days of air temperature (day count appears in upper right) run_Umov -> displays 46 days of wind (day count appears in upper right) run_Emov -> displays 46 days of vapor pressure (day count appears in upper right) view1 -> displays latent & net heat flux, & wind stress(~momentum flux) on 1 day. view6 -> displays up to 6 days (not necessarily consecutive) of user's choice for a single atmospheric variable.Your assignment this week is descriptive. There are several specific questions, but you should also take time to explore the data given with the provided m-files. There's plenty of time to satisfy your curiosity while completing the lab.
Open a Matlab window in your working directory and watch the wind movie (run_Umov). Identify and describe the most common wind pattern over the South China Sea. ( Hint: look for the Winter Monsoon!) Then pick a single day when this pattern is prevalent. Pick a second day when you see a noticeably different wind pattern. Use the 'view6' m-file in Matlab to pinpoint your two days and verify the difference. Next, watch the temperature movie (run_Tmov) to check out the two days you picked from the wind movie.
Now use 'view1' to look at your two days. From the patterns of the atmospheric variables, what do you think has the primary influence on the net heat flux (i.e. thermal forcing) of the ocean? Which day (monsoon or non-monsoon) has the greater net heat flux?
>> plot_SST >> casis([Tmin,Tmax]); >> colorbar;To complete this lab, e-mail the lab instructor at fan@nps.navy.mil with your answers to the