![\"\"](\"https:\/\/www.ssec.wisc.edu\/news\/wp-content\/uploads\/sites\/19\/2019\/08\/Callyn_Bloch_Photo_crop-898x1026.jpg\")
UW-Madison CIMSS research intern Callyn Bloch. Credit: Callyn Bloch<\/p><\/div>\n
Callyn Bloch, a research intern at the University of Wisconsin\u2013Madison Cooperative Institute for Meteorological Satellite Studies (CIMSS), has been studying the problem of underestimated surface-based CAPE values from satellites. Her research has led to a method for improving CAPE accuracy that relies on a combination of ground-based and satellite derived datasets. Bloch\u2019s research results were published in the Journal of Applied Meteorology and Climatology<\/a> in August.<\/p>\n \u201cSevere weather can happen during daytime heating, and we don\u2019t always get those observations between weather balloon launches that occur only once in the morning and once in the evening in the US,\u201d says Bloch. \u201cThat\u2019s the benefit of the satellite profiles, which can capture that missing information.\u201d<\/p>\n A comparison of Convective Available Potential Energy (CAPE) calculations for June 18, 2017, figure a shows CAPE values from the Suomi NPP hyperspectral infrared sounder without the use of ground-based MADIS data. Figure b shows the same date and time but with satellite and ground-based data integrated, resulting in a more accurate CAPE calculation. CAPE values less than 1000 (J\/kg) are considered weak instability, values greater than 4000 (J\/kg) are considered to be extremely unstable. Credit: Callyn Bloch<\/p><\/div>\n A combination approach is used by meteorologists to get a complete picture about the state of the atmosphere at a given time. Weather balloon radiosondes provide crucial data about the Earth\u2019s boundary layer, but satellites struggle to accurately detect changes close to the Earth\u2019s surface. Bloch argues that using satellite data alone (in the absence of boundary layer information) can lead to underestimated CAPE values in cases when the atmosphere is highly unstable.<\/p>\n Bloch cites two instances from June 18, 2017 over the Eastern US and July 3, 2017 over Oklahoma and Texas where strong CAPE values were present and severe weather formed but satellites failed to detect any risk.<\/p>\n To address this problem, Bloch developed a near real-time visualization product that takes advantage of ground-based measurements that are aggregated in NOAA\u2019s Meteorological Assimilation Data Ingest System<\/a> (MADIS). MADIS archives these daily data collected from airports, lake buoys and roadside weather stations. Bloch\u2019s product can then be launched in RealEarth<\/a>, a visualization program developed at the Space Science and Engineering Center.<\/p>\n \u201cCAPE estimations can be sensitive, so if a satellite\u2019s measurements are off by one or two degrees Celsius, it can greatly affect its value,\u201d says Bloch. \u201cWhen we combined the MADIS data with the satellite observations the results were close to those actually observed, nearly identical with the same CAPE boundaries and values.\u201d<\/p>\n![\"\"](\"https:\/\/www.ssec.wisc.edu\/news\/wp-content\/uploads\/sites\/19\/2019\/08\/Screen-Shot-2019-08-26-at-12.36.07-PM-689x1026.png\")