An atmospheric instability derived with MODIS prof

Authors: A K Mitra A K Sharma Ishwar Bajpai P K Kundu

Publish Date: 2012/04/26

Volume: 63, Issue: 2, Pages: 1007-1023

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Abstract

In this study assessing the atmospheric instability a new index named here as MODIS Moderate Resolution Imaging Spectroradiometer profile index MPI has been statistically computed using temperature and moisture profile data from the realtime direct broadcast receiving systems installed at three places of India Meteorological Department The training dataset has been prepared using MODIS temperature and moisture profile from the Aqua and Terra satellites over the Indian region for clear and convective weather conditions during the period of March to June 2011 The MPI values are produced at 5 × 5 km pixel resolution when at least 6 out of 9 FOVs from MODIS granules are found cloud free If more than 3 FOVs are cloudy the MPI has not been computed The formulation of MPI and its comparison have been examined with wellestablished traditionally used K index Lifted Index and total totals index derived from radiosonde profiles of temperature pressure and humidity It has been observed that in most of the cases MPI has well correlated with those derived from ground truth observations Therefore spatially interpolated MPI can be utilized as an indicator for regional and locationspecific forecast over the areas where radiosonde data are not available The results also indicated that MPI can be used as a sensitive measure in very early stages of instability developments such as thunderstorm and rainfall because no other single stability index can provide a distinct threshold value for these events Therefore a single MPI value at a certain threshold can be treated as a stability index instead of other available indices It is also being proposed that the inclusion of MPI as a stability parameter in physical or numerical modeling can improve accurate local severe storm predictions as a useful predictor and can also be used as diagnostic tools The MPI can make a useful simulation using entire temperature and moisture profile data for the assessment of instability significantly to severe weather forecasting since other instability indices are often derived from a fixed pressure level quantity of vertical profile parametersAuthors are very much grateful to Director General of Meteorology IMD New Delhi for his keen interest valuable suggestions and for providing all facilities to complete the work The first author thanks the MODIS group at the University of WisconsinMadison CIMSS for providing the valuable information in this work including Kathy Strabala for applying the MOD07 algorithm into the IMAPP software and Steve Ackerman CIMSS for useful discussions during his visit at CIMSS/SSEC in University of Wisconsin as a visiting scientist The current work was the part of a project done by first author at University of WisconsinMadison USA The authors acknowledge that the TRMM 3B42 V6 rainfall analyses used in this paper were produced with the Giovanni online data system developed and maintained by the NASA GES DISC Authors are grateful to the anonymous reviewers for their valuable comments to improve the quality of the paper

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