![\""Morphed](\"http:\/\/www.ssec.wisc.edu\/news\/wp-content\/uploads\/sites\/19\/2016\/08\/Screen-Shot-2016-08-22-at-11.46.30-AM-600x245.png\")
<\/a>“Morphed composite” satellite imagery of total precipitable water over the world’s oceans from August 19-22, created using the original version of MIMIC-TPW. Click for animation.<\/p><\/div>\n
\u201cThat way, you can take one observation and make it apply to a long stretch of time,\u201d he says. \u201cThat\u2019s what enables you to have a natural-looking visualization.\u201d<\/p>\n
Wimmers and Velden went public with the Morphed Integrated Microwave Imagery at CIMSS – Total Precipitable Water (MIMIC-TPW) algorithm in 2007<\/a>, and it has been an integral tool for tropical weather analysis ever since.<\/p>\n Still, there was room for improvement, particularly to better serve coastal forecasters.<\/p>\n Some polar-orbiting satellites collect Earth data in a conical scanning pattern, so while they are constantly changing position all over the globe, their retrievals are generated from the same scan angle. This allows them to take a very precise measurement, and stay well inter-calibrated with other conical scanners, explains Wimmers. But it meant that the original MIMIC-TPW algorithm (relying entirely on conical-scanning satellite retrievals) was only able to accurately sense TPW over a uniform surface\u2014which, for the most part, is oceans. The emission profile of land, especially with topography, is simply too uneven.<\/p>\n \u201cIt\u2019s a very simple algorithm that gives you a very fast retrieval of TPW over oceanic areas.\u00a0 But it didn\u2019t generate retrievals over land,\u201d says Wimmers, who is the lead developer for MIMIC-TPW.<\/p>\n While this was perfectly fine for users such as the Naval Research Laboratory, a major source of support for MIMIC-TPW, and other users generally interested in forecasting marine weather and tropical cyclone environments, Wimmers and Velden hoped to find an alternative solution that could extend coverage to over land areas.<\/p>\n Then, last year, they got their answer.<\/p>\n The National Oceanic and Atmospheric Administration (NOAA) made significant improvements in the TPW retrieval from its microwave-scanning satellites, which are cross-track scanners (not conical). The new retrievals are comparable in resolution to the DMSP satellites they have always used, Wimmers says.<\/p>\n \u201cThe spatial resolution is not quite as good, but now we have developed an updated algorithm that works at the full scanner resolution, rather than the three-by-three averaging of each sounding, which would have led to much lower resolution,\u201d he explains.<\/p>\n Plus, \u201csince this is a full atmospheric retrieval system, it works over all surfaces including land,\u201d says Wimmers.<\/p>\n This led to the development of a technique called \u201cmorphological compositing\u201d which uses TPW data from every available operational microwave-frequency satellite sensor, produced by a NOAA Center for Satellite Applications and Research (STAR) algorithm<\/a> called the Microwave Integrated Retrieval System (MIRS). The availability of this new TPW retrieval method extends MIMIC-TPW\u2019s coverage above and beyond the original design, providing TPW values over land and sea for the entire globe.<\/p>\n \u201cWe adapted the image-morphing algorithm to work over water and land, and applied it to a more formal coordinate system,\u201d explains Wimmers. \u201cWhat we were doing before was essentially a shortcut\u2014it only needed to apply to the tropics. This new method makes it work in global coordinates.\u201d<\/p>\n
![\"Global](\"http:\/\/www.ssec.wisc.edu\/news\/wp-content\/uploads\/sites\/19\/2016\/08\/Screen-Shot-2016-08-22-at-11.47.58-AM-600x282.png\")
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