Measurements from HIRDLS are used to quantify gravity wave momentum fluxes generated from monsoon regions across the globe over the three years 2005-2007.

Momentum fluxes in the altitude range 16-60km over monsoon regions in both hemispheres show good correlations with convective data from NOAA's Outgoing Longwave Radiation time series and precipitation data from the Tropical Rainfall Monitoring Mission. A temporary increase in measured momentum flux, of approximately 50% over temporal background values, is observed during the ~4 month boreal monsoon period over the 10N-30N latitude band, with around half of the annual momentum flux for this latitude range measured during this period.

Above: a strong gravity signal observed over the Andes in mid-2006.

Above: longitude-time plot of: (top) HIRDLS gravity wave momentum flux in 0.2-100 mb pressure region, (middle) TRMM precipitation and (bottom) NOAA OLR, showing sharp monsoon peaks for the Indian, American and African monsoons.