1004 Global Wind Observations Capitalizing on Doppler Wind Lidar Synergisms with other Wind Measuring Systems

Wednesday, 25 January 2017
4E (Washington State Convention Center )
George D. Emmitt, Simpson Weather Associates, Charlottesville, VA; and S. Greco and S. A. Wood

The general call for global 3D winds was well documented in the last NRC Decadal survey and the need remains just as strong today if we are to realize the “transformational” advances in NWP and climate modeling that have been called for.  This is best exemplified by the following recent statement published in NASA’s 2015 Workshop Report on Scientific Challenges and Opportunities: “Global measurements of the spatiotemporal (four-dimensional) evolution of large-scale horizontal wind vectors are urgently needed. It is important to avoid all or nothing strategies for the three-dimensional wind vector mea­surements, as important progress is possible with less than comprehensive observing strate­gies”.

Numerous road maps to space have been presented for the use of Doppler Wind Lidar to provide global winds, yet these roadmaps have mainly been technology centric. The plan and roadmap presented here is more measurement centric and relies on synergisms between DWL and other existing or planned wind measuring systems.

 The effect of clouds and the performance of wind measuring instruments in the presence of clouds is a specific focus that will be discussed. Early space wind mission concepts favored higher pulse energies for coherent wind lidar since aerosol backscatter sensitivity is improved proportionally with pulse energy multiplied by square root of pulse rate (not the laser average power). However, space mission simulations have revealed the large effect of clouds on mission performance. A higher pulse rate laser would increase the probability of some laser shots penetrating the porosity of the partly cloudy scenes and would lower the representativeness error of the wind measurement for assimilation in NWP models. Based on these considerations, we make a case to utilize a higher pulse rate 2-micron coherent lidar that was initially designed for measurement of carbon dioxide column content.

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