Laboratory for Remote Sensing and Geoinformatics 　 Directed by  Dr. Hongjie Xie , Assistant Professor

Moderate Resolution Imaging Spectroradiometer (MODIS)

Introduction

NASA's two MODIS sensors, on both Terra and Aqua Earth observing satellites since February 2000 and May 2002, respectively, provide tremendous data of globe coverage in twice per day with spatial resolution of 250 m to 1 km. The MODIS instrument provides high radiometric sensitivity (12 bit) in 36 spectral bands ranging in wavelength from 0.4 µm to 14.4 µm. A ±55 degree scanning pattern at the sun synchronous orbit of 705 km achieves a 2,330 km swath. The near-real time and free downloadable geophysical products includes land surface reflectance (MOD09 and MOD43),snow cover (MOD10), land surface temperature & emissivity (MOD11), land cover/land cover change (MOD12), vegetation indices (MOD13), thermal anomalies, fires & biomass burning (MOD14), leaf area index and FPAR (MOD15), evapotranspiration (MOD16), net photosynthesis and primary productivity (MOD17). However, the data is difficult for users to easily use due to two reasons (1) the EOS-HDF format is not currently fully supported by commercial image processing software packages such as ENVI, Erdas Imagine, and PCI, which most remote sensing persons are commonly using; (2) to get the time series of daily, 8-daily, or 16-daily data for a particular area, automated batch processing tools are needed, which are not currently available through those commercial packages.  These factors above are seriously hindering researchers from the rapid acquisition and retrieval of time series MODIS geophysical products for various purposes such as environment monitoring and management.  It usually takes months for a new user to figure out the data format and the needed tools to process and convert data, and then extract useful information for such purposes (see a document introducing MODIS products).

Objectives

One goal of the project is to use the MODIS Reprojection Tool (MRT) and batch processing scripts that Dr.Xie have developed to (1) retrieve, mosaick, and convert above datasets (MODIS Level 2-4 from February 2000 to present) into friendly used data and projection formats covering the Texas (Figure 1) and (2) establish a GIS-based geodatabase and make these data available through internet in a near-real time fashion (Xie et al. 2004, 2005, Zhou et al. 2005). Once will be done, these data will be available for downloading through both the LRSG and TexasView. Please check back with us.        

The other goal is to use these data to study and monitor the environmental system and its dynamic changes in water resources, sediments sources, pollution sources, land use, wetland, shoreline, ecological diversity, to name a few.

　

Figure 1. Texas covered by 5 MODIS titles

References:

Xie, H., X. Zhou, E.R. Vivoni, J.M.H. Hendrickx, E.E. Small, 2005, GIS Based NEXRAD Precipitation Database: Automated Approaches for Data Processing and Visualization. Computers and Geosciences, Vol.31 (1), pp 65-76 (pdf).

X. Zhou, H. Xie, J. Hendrickx, 2005, Statistical evaluation of MODIS snow cover products with constraints from streamflow and  SNOTEL measurement. Remote Sensing of Environment, Vol.94 (2), pp214-231 (pdf).

H. Xie, X. Zhou, and J. Hendrickx, 2004, Evaluation of MODIS snow-cover products with constraints from streamflow and SNOTEL data, AGU Fall Meeting, December 13-17, San Francisco, California