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CAMEX-4 High Altitude MMIC Sounding Radiometer (HAMSR) Table of Contents
The High Altitude MMIC Sounding Radiometer (HAMSR) is a microwave atmospheric sounder recently developed by JPL under the NASA Instrument Incubator Program. Using new technology, it is a small but accurate instrument that is well suited for hurricane studies. Operating with 25 spectral channels in the 50 - 190 GHz region, it provides measurements that can be used to infer the 3-D distribution of temperature, water vapor, and liquid water in the atmosphere, even in the presence of clouds. Parameters related to scattering from ice particles aloft as well as precipitation can also be inferred. During CAMEX-4, HAMSR was mounted in a wing pod of a NASA ER-2 research aircraft, which operates at an altitude of 65,000 feet and therefore can overfly hurricanes. HAMSR is a self-calibrating cross-track scanning instrument. The scan mirror makes a full revolution in a little more than 1 second. During that period it obtains a number of overlapping spatial samples of the scene below and several views of two internal calibration targets. From an altitude of 20 km the scan width is about 40 km wide on the ground with a single field of view of 2 km at nadir. Sampling intervals are 1 km cross-track. Brightness temperatures are collected for each field of view using 25 channels in 3 spectral bands. Band I, which is a temperature sounding band near 118 GHz, was not operational during CAMEX-4. The remaining 15 channels are divided between the 8-channel 54-GHz temperature sounding band II, and the 7-channel 183-GHz humidity sounding band III. Additional information about the HAMSR instrument may be found in the PDF document Hurricane Studies With HAMSR. Data ProductsThe primary derived measurements are vertical profiles of temperature, water vapor and liquid water, from the surface to 100 mb in 2-4 km layers. Daily flight information is found in the document CAMEX_summary.pdf. Data FormatData are 'tarred' into daily (mission) data files of the form:
where c4ehamsr represents CAMEX4 and the HAMSR instrument, yyyy.ddd is the four digit year and day of year, fff is the mission number. When untarred, this will yield two data files; one in binary and one in HDF format. File naming convention for the data files is:
where HAMSR identifies the instrument, 2km is the resolution, yymmdd is the year, month and day, 1 is the data set number (named by the scientist), 1100 is the time in GMT, and the file extension is either bin or hdf for either binary or HDF files. See this HAMSR Binary File Description or this HAMSR HDF File Description. The HDF format may be read using any common HDF reader. More information about HDF may be found at the HDF homepage. Contact InformationTo order these data or for further information, please contact:
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