Ultra-spectral sounders (USS) in low earth orbit have significantly improved weather forecast accuracy in recent years, and their impact could be significantly improved with reduced revisit times. The GeoMetWatch, Inc.1 Sounding and Tracking Observatory for Regional Meteorology (STORMTM) program is designed to place a constellation of six USS units in spaced geostationary (GEO) positions around the earth. From GEO, the repeat time for a specific weather feature can be reduced to minutes, and the vertical temperature, water vapor and wind profiles can provide detailed warnings not available by any other means. The STORMTM sensor, a derivative of the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) EDU that was designed and built for NASA by Utah State University (USU) and rigorously tested in 2006, will be launched on a commercial geostationary satellite in late 2016. It combines advanced technologies to provide improved performance and reliability over the original EDU. From GEO the USS can observe surface thermal properties and atmospheric weather and chemistry variables in four dimensions. This paper provides an overview of the STORMTM instrument and the measurement concept. STORMTM’s USS will provide data of the same quality as the current LEO satellite sounders (AIRS, CrIS, and IASI) but with the ability to track storm development with soundings and images at any desired rate. Wind profiles obtained from a time sequence of STORMTM water vapor retrieval images will provide additional input to now casting and regional models.
Several studies have shown that a geostationary hyperspectral imager/sounder can provide the most significant value increase in short term, regional numerical prediction weather models over a range of other options. In 1998, the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) proposal was selected by NASA as the New Millennium Earth Observation 3 program over several other geostationary instrument development proposals. After the EO3 GIFTS flight demonstration program was changed to an Engineering Development Unit (EDU) due to funding limitations by one of the partners, the EDU was subjected to flight-like thermal vacuum calibration and testing and successfully validated the breakthrough technologies needed to make a successful observatory. After several government stops and starts, only EUMETSAT’s Meteosat Third Generation (MTG-S) sounder is in operational development. Recently, a commercial partnership has been formed to fill the significant data gap. AsiaSat has partnered with GeoMetWatch (GMW)1 to fund the development and launch of the Sounding and Tracking Observatory for Regional Meteorology (STORMTM) sensor, a derivative of the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) EDU that was designed, built, and tested by Utah State University (USU). STORMTM combines advanced technologies to observe surface thermal properties, atmospheric weather, and chemistry variables in four dimensions to provide high vertical resolution temperature and moisture sounding information, with the fourth dimension (time) provided by the geosynchronous satellite platform ability to measure a location as often as desired. STORMTM will enhance the polar orbiting imaging and sounding measurements by providing: (1) a direct measure of moisture flux and altitude-resolved water vapor and cloud tracer winds throughout the troposphere, (2) an observation of the time varying atmospheric thermodynamics associated with storm system development, and (3) the transport of tropospheric pollutant gases. The AsiaSat/GMW partnership will host the first STORMTM sensor on their AsiaSat 9 telecommunications satellite at 122 E over the Asia Pacific area. GMW’s business plan is to sell the unique STORM data and data products to countries and companies in the satellite coverage area. GMW plans to place 6 STORMTM sensors on geostationary telecommunications satellites to provide global hyperspectral sounding and imaging data. Utah State University’s Advanced Weather Systems Laboratory (AWS) will build the sensors for GMW.
Precise measurements of CH4 in a column of near surface air, and in partial columns above this, would be very valuable in identifying sources/sinks of atmospheric CH4, and its transport. For this purpose we have proposed a grating mapping spectrometer (GMS) for deployment as an Instrument of Opportunity (IOO) on the NPOESS that acquires data in the 2990 to 3050 cm-1 spectral region. It will provide measurements of CH4 absorption of sunlight in the weaker CH4 features in the region, and of thermal emission in the stronger CH4 features in the region. It is the combination of the two that provides the vertical information. The IOO will acquire spectra on a crosstrack swath centered on nadir, and with 1/2 width of 55 degrees on each side of nadir (about 2800 km full width swath on the ground for a nominal 828 km satellite altitude). This with footprints that are about 3.1 km on a side at nadir. The small footprint facilitates cloud screening, and identification of CH4 source hotspots. A capability to project the slit to nadir along the direction from satellite to sun will be utilized for over the ocean viewing in order to facilitate measurements in solar glitter. It will obtain spectra with resolution n < 0.58 cm-1 and sample spacing < 0.17 cm-1. Based on the spectral characteristics and currently achievable very low-noise we do a linear error analysis (Rodgers, ) for the simultaneous retrieval of multi-column CH4, humidity, and surface parameters and 13CH4 total column. We show that useful multi-column CH4 retrievals can be obtained, with good near surface sensitivity in sunlit conditions. We also show the 13CH4 column can be retrieved with precision better than 3%. Retrieval of 13CH4 column in the earth's atmosphere is analogous in difficulty to retrieval of the major CH4 isotope column in the Martian atmosphere by a similar GMS deployed on a Mars orbiter. We show that H2O vertical information can be retrieved from these measurements and discuss the potential for ethane column retrieval.
Measurements of the column CH4, CO and CO2 are high priorities of the NPOESS Pre-Planned Product Improvement (P3I) data sets. Risk reduction for existing NPOESS instruments, including mitigation of daytime CO2 SWIR non-LTE effects, is also a high priority. We have proposed an NPOESS Instrument Of Opportunity (IOO) to address these priorities. It consists of two grating mapping spectrometers (GMSs). One that would acquire measurements with high spectral resolution Δv < 0.13 cm-1 of CH4, CO and H2O absorption lines in reflected sunlight in the VSWIR region 4281 to 4301 cm-1, and another for measurements with Δv < 0.30 cm-1 in the SWIR region 2355 to 2430 cm-1. The IOO will acquire spectra on a crosstrack swath from nadir to 55 degrees (about 1400 km on the ground) on footprints that are about 1.55 and 3.1 km on a side at nadir for the two GMS, respectively. The small footprint facilitates cloud screening, and identification of pollution hotspots. We use linear error analysis (LEA, based on the Rodgers  paper) to estimate the proposed IOO's performance. The LEA indicates that the IOO should be able to provide CH4 and CO column retrieval over sunlit land (and from ocean glitter when it is viewed) that satisfies or exceeds NPOESS P3I Environmental Data Records (EDRs) requirements in all aspects except refresh where the IOO would provide every two days vs the once per day requirement. Further, it shows the VSWIR IOO data when used in combination with the NPOESS Cross Track Infrared Sounder (CrIS)  data should provide: (a) CO profile data with sensitivity to CO in near surface air that is enhanced compared to that in the current TERRA-MOPITT, ACQUA-AIRS and AURA-TES data sets because these are limited to thermal infrared measurements that lack sensitivity to CO in near surface air layer where there is little contrast between the air temperature and the ground surface temperature, (b) CH4 profile with sensitivity in the near surface air layer that is crucial for identifying CH4 sources/sinks (c) and significant improvement in the CrIS retrieved humidity in the near surface layer of air. We show the SWIR IOO data can be used for CO2 column retrieval with near surface air layer sensitivity in the daytime. And also that in combination with CrIS SWIR data facilitates CO2 SWIR non-LTE mitigation that is required for advanced sounding quality temperature profile (TP) retrieval from CO2 SWIR data in daytime conditions. This provides risk reduction in case of degradation in the CrIS LWIR region data.
As Space Weather makes the transition from a research to an operational mode, the need for reliable and relevant datasets will be of paramount importance. Good research data will not necessarily be good operational data, we will discuss some reasons why. The first order data inputs required for the developing suite of Space Weather Forecast models (GAIM, CISM, EPPIM, etc) need to be identified at an early stage so that adequate observational networks (space and ground based) can be put into place. Lessons learned from decades of operational meteorological forecast systems should be applied. Ranking, relevance and cost-benefit decisions need to be performed on each component of the Operational Space Weather system to insure that the maximum amount of capability is obtained at a reasonable cost. We will examine a range of proposed space weather data inputs and attempt to apply these criteria to each of them.
Conference Committee Involvement (6)
High-Performance Computing in Remote Sensing
22 September 2014 | Amsterdam, Netherlands
Satellite Data Compression, Communications, and Processing X
8 May 2014 | Baltimore, Maryland, United States
High-Performance Computing in Remote Sensing III
25 September 2013 | Dresden, Germany
High-Performance Computing in Remote Sensing
26 September 2012 | Edinburgh, United Kingdom
High-Performance Computing in Remote Sensing
19 September 2011 | Prague, Czech Republic
Multispectral, Hyperspectral, and Ultraspectral Remote Sensing Technology, Techniques, and Applications