L. Chiu | GMU - Academia.edu (original) (raw)

Papers by L. Chiu

Oceanic fresh water flux is an essential component of the global water cycle and plays an importa... more Oceanic fresh water flux is an essential component of the global water cycle and plays an important role in forcing the oceanic circulation. However, its mean state, short-term variability and long-term changes are poorly monitored and documented due to undesirable quality of the data sets for its two primary components, precipitation (P) and evaporation (E). While fields of oceanic precipitation and evaporation are routinely

ABSTRACT Using NASA satellite remote sensing data from multiple sources for hydrologic applicatio... more ABSTRACT Using NASA satellite remote sensing data from multiple sources for hydrologic applications can be a daunting task and requires a detailed understanding of the data's internal structure and physical implementation. Gaining this understanding and applying it to data reduction is a time-consuming task that must be undertaken before the core investigation can begin. In order to facilitate such investigations, the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) has developed the GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure or "Giovanni," which supports a family of Web interfaces (instances) that allow users to perform interactive visualization and analysis online without downloading any data. Two such Giovanni instances are particularly relevant to hydrologic applications: the Tropical Rainfall Measuring Mission (TRMM) Online Visualization and Analysis System (TOVAS) and the Agricultural Online Visualization and Analysis System (AOVAS), both highly popular and widely used for a variety of applications, including those related to several NASA Applications of National Priority, such as Agricultural Efficiency, Disaster Management, Ecological Forecasting, Homeland Security, and Public Health. Dynamic, context- sensitive Web services provided by TOVAS and AOVAS enable users to seamlessly access NASA data from within, and deeply integrate the data into, their local client environments. One example is between TOVAS and Florida International University's TerraFly, a Web-enabled system that serves a broad segment of the research and applications community, by facilitating access to various textual, remotely sensed, and vector data. Another example is between AOVAS and the U.S. Department of Agriculture Foreign Agricultural Service (USDA FAS)'s Crop Explorer, the primary decision support tool used by FAS to monitor the production, supply, and demand of agricultural commodities worldwide. AOVAS is also part of GES DISC's Agricultural Information System (AIS), which can operationally provide satellite remote sensing data products (e.g., near- real-time rainfall) and analysis services to agricultural users. AIS enables the remote, interoperable access to distributed data, by using the GrADS-Data Server (GDS) and the Open Geospatial Consortium (OGC)- compliant MapServer. The latter allows the access of AIS data from any OGC-compliant client, such as the Earth-Sun System Gateway (ESG) or Google Earth. The Giovanni system is evolving towards a Service- Oriented Architecture and is highly customizable (e.g., adding new products or services), thus availing the hydrologic applications user community of Giovanni's simple-to-use and powerful capabilities to improve decision-making.

For growing needs of knowledge on worldwide food supply, USDA and NASA have been developing an Ag... more For growing needs of knowledge on worldwide food supply, USDA and NASA have been developing an Agricultural Information System (AIS), which can be globally applied. One of the essential input parameter for AIS is precipitation that should be spatially and temporally consistent. TRMM precipitation products can satisfy this condition with relatively low cost than in situ rain rate measurements. For

Variations of the oceanic evaporation of recent years were examined using latent heat flux derive... more Variations of the oceanic evaporation of recent years were examined using latent heat flux derived from Special Sensor Microwave Imager (SSM/I) on board the Defense Meteorological Satellite Program (DMSP) satellites. Analysis of the version 2 of the Goddard Sea Surface Turbulent Flux (GSSSTF2) data set shows an increase of global oceanic evaporation of 17 percent over the period July 1988-December

IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174), 1998

ABSTRACT

Trends and variability in global oceanic evaporation data sets have been examined for the period ... more Trends and variability in global oceanic evaporation data sets have been examined for the period 1988-2000 by Chiu et al. (Acta Oceanologica Sinica, 2008). These data sets are satellite estimates based on bulk aerodynamic formulations and include the NASA/Goddard Space Flight Center Satellite-based Surface Turbulent Flux version 2 (GSSTF2), the Japanese-Ocean Flux Using Remote Sensing Observations (J-OFURO), the Hamburg Ocean-Atmosphere

The Tropical Rainfall Measuring Mission (TRMM), a joint mission between NASA and the Japan Aerosp... more The Tropical Rainfall Measuring Mission (TRMM), a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA), has been acquiring data from shortly after its launch in November 1997 to the present. All TRMM data, including those from the first and, thus far, only space-borne Precipitation Radar (PR), are archived at and distributed by the GES DISC DAAC. As

Encyclopedia of Physical Science and Technology, 2003

We compare monthly and seasonal rain rates derived from the TRMM version 5 Precipitation Radar (T... more We compare monthly and seasonal rain rates derived from the TRMM version 5 Precipitation Radar (TPR, TSDIS reference 2A25), TRMM Microwave Imager (TMI, 2A12), TRMM Combined Instrument (TCI, 2B31), TRMM calibrated IR rain estimates (3B42) and TRMM merged gauge and satellite analysis (3B43) algorithms. The domain average rain rate over the period January 1998 -- December 2003 are 2.99, 2.30, 2.43, 2.66 and 2.60 mm/day, respectively, for TMI, TPR, TCA, 3B42 and 3B43. Paired-t tests showed that there is no significant difference between TPR and TCI, while significant differences between TMI and TPR exist. The TMI is significantly higher than TPR in the major oceanic rain belts, over the Amazon and in southern Africa, but is lower in the oceanic dry regions and in some mountainous areas. The merged satellite rain rate (3B42) is significantly higher than the merged gauge and satellite analysis (3B43) over land, but shows little difference over the ocean, except in oceanic dry regions. Tem...

The Tropical Rainfall Measuring Mission (TRMM) has acquired more than four years of data since it... more The Tropical Rainfall Measuring Mission (TRMM) has acquired more than four years of data since its launch in November 1997. TRMM is a joint U.S.-Japan mission to monitor and study tropical and subtropical rainfall systems. All TRMM standard products are processed by the TRMM Science Data and Information System (TSDIS) and archived and distributed to general users by the GES DAAC. As of February 28, 2002, a total of 457,639 files (12.5 TB) have been archived and 3,192,230 files (74.8 TB) distributed. The Utilization Ratio (UR), defined as the ratio of the number of distributed files to the number of archived files, of the TRMM standard products has been steadily increasing since 1998 and is currently at 6.98. In addition to the standard products, the GES DAAC generates and/or maintains a set of derived TRMM products (e.g., coincidence subsets, resampled gridded subsets, parameter subsets, GIS compatible files, and GrADS files) to facilitate public usage of the TRMM data. The high dat...

Proceedings of SPIE - The International Society for Optical Engineering, 2002

Remote sensing and GIS for regional environmental applications. [Proceedings of SPIE 4886, 1 (200... more Remote sensing and GIS for regional environmental applications. [Proceedings of SPIE 4886, 1 (2003)]. Menas Kafatos, Hesham El-Askary, Long S. Chiu, Richard B. Gomez, Mohamed Hegazy, Jason M. Kinser, Xue Liu, Yang ...

Remote Sensing of Clouds and the Atmosphere VII, 2003

Journal of Applied Meteorology, 1993

Geophysical Research Letters, 1999

We evaluated the performance of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (... more We evaluated the performance of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) at-launch algorithm for monthly oceanic rain rate using six months (January-June 1998) of TMI data. Comparison with oceanic monthly rain rates derived from the Special Sensor Microwave Imager (SSM/I) data shows statistically significant differences. The TMI rain rates are lower than the SSM/I rain rates by

Satellite remote sensing for disease surveillance will play a major role in public health in the ... more Satellite remote sensing for disease surveillance will play a major role in public health in the coming years. Although the ability to predict epidemic outbreaks is still limited by current research and technology, satellite remote sensing has the potential to become an important tool for assisting epidemiologists in locating areas where disease outbreaks are likely to occur. This will permit