The Earth Observer

Among other leading officials present at the meeting were Yukio Haruyama of the Japanese National Space Development Agency (NASDA) and Toshifumi Sakata of Tokai University (the host institution). (Dr. Sakata chairs Japan's Earth Environment Observation Committee.)

Ramesh Kakar, the TRMM Program Scientist (NASA Headquarters), thanked the Japanese for setting up the meeting, and Cheryl Yuhas (NASA Headquarters) said that the Memorandum of Understanding (MOU) between Japan and the U.S. for the TRMM program had been signed, as of October 20, and the joint program was now official. Kakar then went on to discuss developments regarding the ground-based rain-measuring radar to be installed at Kwajalein as part of the overall ground validation network.

Tom LaVigna, the TRMM Project Manager (GSFC), gave the current status of the TRMM Project. He said that most of the flight hardware has been delivered, and the Project is officially on schedule for an August 1997 launch, although the funding is tight.

LaVigna reviewed several major concerns he had for the TRMM program. Foremost among them was his concern for the consequences of a potential launch delay. He showed the effects of varying from the originally planned August 1997 date to possible delayed dates of November 1997 or February 1998. The shift to November is likely because of NASDA's need to accommodate the COMETS mission. The further delay until February would be caused by the limited launch periods that have been agreed to by the Japanese fishermen's union.

The delays have consequences that are related to the increased solar activity that has been predicted for these future years. With increased activity and, therefore, more atmospheric drag, the rate of fuel expenditure increases. Then the days of marginal mission life decrease substantially, and the required number of orbital maneuvers increases. In view of these troubling predictions, LaVigna has asked NASDA to increase the TRMM mass allocations to preserve mission life.

Seiichi Ueno (NASDA/EORC) reviewed the status of the precipitation radar (PR) instrument, which is being developed by Japan for the TRMM mission. In his review he noted the problem that had been encountered with the failure of some of the low-noise amplifiers. As a result of the failures, the engineering model of the PR is being refurbished and being delivered to GSFC in December 1995 for mechanical integration and the electrical interface test in advance of the delivery of the flight model.

Tom Wilheit (Texas A&M University) gave a presentation on the TRMM Microwave Imager (TMI). He said that the TMI is a very mature instrument that is based on the successful Special Sensor Microwave/Imager (SSM/I) instrument and noted that the flight version has been delivered to GSFC.

Bob Adler (NASA/GSFC) gave a status report on the TRMM Visible Infrared Scanner (VIRS) instrument. VIRS meets all the noise specifications and will serve as a calibrator for data from the geosynchronous satellites. It also will be a valuable contributor to the development of combined instrument data products. Of itself, it might contribute to the detection of biomass burning.

Following the morning break, Yukio Haruyama (NASDA) described the Japanese Earth study program and showed the schedules for various Japanese Earth Observations programs.

At this point Tsuyoshi Nitta gave a presentation on the negative impacts of the possible TRMM launch delays. In this presentation Nitta referred again to the loss of useful mission life that had been brought up by LaVigna. Then he discussed other negative impacts due to loss of overlap with other missions that have already been scheduled.

Nitta described the overall progress being made in the area of Japanese TRMM science activities and followed this with a discussion of the NASDA TRMM Science Program document, which corresponds to the NASA Science Operations Plan (SOP).

As U.S. TRMM Project Scientist, Joanne Simpson (GSFC) described the status of the U.S. TRMM science program. She said that U.S. TRMM science is focused on launch algorithms, validation data, field programs, and the SOP. All "day one" science algorithms have been selected.

TRMM's new approach to ground validation plans is based on the concept that "quality is more important than quantity." It is necessary to work with data from both ground and space. Data from TRMM ground sites are regarded as one of several data sets to determine rainfall amount and radar echo structure. The four primary ground validation sites are Melbourne (Florida), Darwin, Kwajalein, and Houston. Data from these sites will be processed continuously by the TRMM Science Data and Information System (TSDIS), and each site will have a Principal Investigator (PI). Florida and Texas will operate four high-quality radars, monitoring 600 by 600-km areas and developing water budgets.

Special "climate" sites will have PI-operated radars and operate 3-4 months per year. These sites are São Paolo (Brazil), Israel, Thailand, Guam, Hawaii, and Taiwan.

The agreed minimum of field programs calls for one over water and one over land. Cooperation with existing field programs such as LBA [LAMBADA (Large-Scale Atmospheric Moisture Balance using Data Assimilation); BATERISTA (Biosphere-Atmosphere Transfer and Ecological Research In situ Studies in the Amazon); AMBIACE (Amazon Biology and Atmospheric Chemistry Experiment)] is particularly desired because of the limited funding for such activities. Kwajalein, as the primary ocean site, will provide crucial observations.

Following a lunch break there was a presentation by Erich Stocker (GSFC) on TSDIS status and science algorithm configuration management; and then Makoto Satake (NASDA/EOC) reported on the development status of the Japanese EOC/TRMM Data Processing System. Seiichi Ueno followed with a discussion of the status of the Japanese Earth Observation Information System (EOIS) Data Analysis System (DAS).

Tsuyoshi Nitta presented a draft version of the Joint TRMM Science Team (JTST) "Top-Level Agreement" for approval by the JTST members. (Copies of the Top-Level Agreement with agreed-upon changes may be obtained from the office of the U.S. TRMM Project Scientist by sending requests to Tricia Gregory: gregory@agnes. gsfc.nasa.gov).

Following the afternoon break, Tom Wilheit reported on TMI progress on the U.S. side. He reported the good news that the physically based algorithms are converging, and that an improved "beam filling" correction scheme has been developed. It has been shown that the beam filling error is directly proportional to the freezing level height.

Eric Smith (Florida State University) gave an update on TRMM "combined algorithms," specifically, PR/TMI combined algorithms. The team has defined three options for PR/TMI combined algorithms: augmented radar (narrow swath); augmented radiometer (wide swath); and tall vector (narrow swath). The first option has been selected for the "day 1" solution, and there have been successful tests of the type 1 approach for typhoon Oliver.

Thursday December 14

The first speaker of the morning was Bob Adler (GSFC) on "TRMM with Other Satellites." The concept is to use TRMM as a "flying rain gauge" to improve the global precipitation index (GPI) derived from the geosynchronous satellite data. Adler noted that this way of combining data overcomes the TRMM limited-sampling problem but has the weakness that TMI does not offer a good contribution over land. Combining TRMM products with other satellite data gives finer resolution; thus 1-degree-by-1-degree and 5-day-resolution data could be available.

Bob Houze (University of Washington) addressed ground validation (GV), discussing the two topics of building up climatology and short-term field programs. He noted that the complex flow of GV activities, starting in December 1994, would be the first example of building a climatological program along with satellite flights on a quasi-operational basis.

The recognized ultimate goal of TRMM is to determine the 4-dimensional heating of the atmosphere. The problem comes down to determining divergence as the indicator of the vertical heating gradient, and aircraft measurements can be used to obtain the divergence profiles.

Tom Wilheit gave an update on the status of Physical Validation. Wilheit said that determination of oceanic rainfall is the real ground validation problem, but space observations over ocean will be at their best because of the ocean's uniform characteristics. He cited the principal results from the GV workshop and said that variability in the vertical structure of the hydrometeors was the principal source of error. He asserted that the quality of the TMI measurements is certain to be better than that of all previous spaceborne microwave radiometer measurements.

Otto Thiele (GSFC) described the U.S. TRMM Global Validation Program (GVP). He showed the TRMM GV sites and the data flow. March 1996 is the date for the start of version 3 GV product processing, with Brazil serving as a prototype facility. In the period January to August 1997, GV products are to be produced "commensurate with the planned TRMM overpass schedule."

Kenji Nakamura (Nagoya University) spoke on Japanese calibration/validation activities. Routine data will come from Japan Meteorological Agency radars and the Automated Meteorological Data Acquisition System (AMeDAS). Overpass data will be supplied by the Communications Research Laboratory (CRL) and middle and upper atmosphere (MU) radars. Campaign experiments are planned for the Kanto plain, the MU radar site, and the Ishigakijima Island. Houze said that data from the 14-scan radar on Ishigakijima Island would be good to have as a TRMM direct product.

Krishnamurti (Florida State University) reported for the U.S. TRMM Modeling and Data Analysis Group, stressing the particular value of the GSFC Cloud Ensemble Model (GCEM). The GCEM is being used to validate TRMM rainfall derivation algorithms and convective and stratiform rainfall partitioning schemes, using data from other experiments such as TOGA/COARE. As part of the Modeling Group Bill Lau's team is studying the various monsoon-related phenomena. The Florida State University physical initialization studies seem to show that rain rates are not as important as rain locations.

Tetsuo Nakazawa (MRI) described the activities of the Japanese Modeling and Data Analysis Team. He listed research and application studies, divided into the categories of fundamental and applied: Fundamental studies are devoted to the establishment of the space-time characteristics of tropical rainfall; the establishment of the cloud physics of tropical rainfall systems; and the understanding of rainfall systems in the subtropical rainfall zone. Application studies include improving the predictability of a forecasting model; improving forecast skills for global environmental variations; and learning how to reduce the potential for disasters.

In the next session, Toshiaki Kozu (CRL) described work that is being done on the cross calibration of the Airborne Rain Mapping Radar (ARMAR) and the CRL Airborne Multiparameter Precipitation Radar (CAMPR).

Following the Thursday lunch break, Tom LaVigna (GSFC) introduced a group presentation on satellite maneuvers and the instrument operations planning and coordination process at Goddard. In his introduction he said that TRMM will have carry-over benefits to other space projects as well because it has led the way in developing spacecraft surfaces that will protect against erosion due to atomic oxygen in the outer atmosphere that will be encountered during TRMM's long stay in relatively low orbit.

Makoto Satake (NASDA/EOC) addressed a number of topics that needed to be discussed or coordinated at the JTST meeting. He particularly mentioned data and algorithm sharing issues. Chris Kummerow (GSFC) addressed strategy and procedures for developing algorithm version upgrades. He said that the remaining problem is how to know whether a new algorithm is better than the previous algorithm.

Friday, December 15

The final session opened with a discussion by Kakar on research announcements. He said that another NASA Research Announcement (NRA) is needed to provide funding for the period after the TRMM launch. A target date for this announcement would be the end of FY 96.

Seiichi Ueno led the final summary/wrap-up review. The first order of business was a review of a previously drafted statement on launch delays. Next, Ueno presented a chart showing the schedule of the second Japan Research Announcement (JRA), which generally parallels the schedule of the U.S. NRA. Modifications to the "Joint TRMM Science Team Top-Level Agreement" were also reviewed.

As the meeting came to an end, Kakar thanked the Japanese side for agreeing to host the very rewarding meeting in Hawaii. Simpson voiced her appreciation as well. Haruyama also thanked all for coming and for having the meeting in Hawaii. Finally, Nitta expressed his thanks to all and said that he was glad that an agreement had been reached on algorithm development.

|Table of Contents| |Previous| |Next|