Mountain wave turbulence in the western US

February 14th, 2011 |

GOES water vapor images with pilot reports of turbulence (click image to play animation)

GOES water vapor images with pilot reports of turbulence (click image to play animation)

Strong southwesterly winds aloft interacting with the rugged terrain of the Sierra Nevada mountain range resulted in a number of pilot reports of mountain waves which were producing moderate turbulence over parts of the western US on 14 February 2011. AWIPS images of a composite of 8-km resolution GOES-11 (GOES-West) and 4-km resolution GOES-13 (GOES-East) water vapor imagery (above) revealed a classic mountain wave signature just downwind of the Sierra Nevada. The “seam” between GOES-11 and GOES-13 is fairly evident on the AWIPS water vapor image composite, mainly due to the difference in spatial resolution.

A comparison of the mountain waves on the 8-km resolution GOES-11 6.5 µm water vapor image versus the corresponding 1-km resolution Terra MODIS 6.5 µm water vapor image (below) demonstrates the clear advantage of improved spatial resolution for detecting the areal coverage of such features.

GOES water vapor image + MODIS water vapor image (with pilot reports of turbulence)

GOES water vapor image + MODIS water vapor image (with pilot reports of turbulence)

About 1.5 hours later, a similar comparison of the mountain waves on the 8-km resolution GOES-11 6.5 µm water vapor image versus the corresponding 1-km resolution Aqua MODIS 6.5 µm water vapor image can be seen below. Note that there is less “striping” (due to detector degradation) on the Aqua MODIS water vapor image — Aqua is a newer satellite , launched in 2002 (Terra was launched in 1999) .

GOES water vapor image + MODIS water vapor image (with pilot reports of turbulence)

GOES water vapor image + MODIS water vapor image (with pilot reports of turbulence)