ESTIMATING OF CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) WITH IN-SITU AND SATELLITE HYPERSPECTRAL REMOTE SENSING TECHNOLOGY Yong Q. Tian 1 , Qian Yu 2 , and Weining Zhu 1 1 Department of Geography/Institute for Great Lakes Research Central Michigan University, Mt. Pleasant, MI. 48859, USA E-mail: yong.tian@cmich.edu 2 Department of Geosciences, University of Massachusetts Amherst, MA. 01003, USA Keywords: Chromophoric dissolved organic matter (CDOM), dissolved organic carbon (DOC), EO-1 Hyperion, Hyperspectral data, Ocean color, Coastal Environmental, QAA-CDOM ABSTRACT The influence of land surface characteristics and climate conditions on the source, quantity, quality, and timing of dissolved organic carbon (DOC) fluxes to coastal waters is not well understood. The significant correlation between DOC and chromophoric dissolved organic matter (CDOM) leads to an increasing need of CDOM monitoring for understanding the DOC land- water dynamics. This study is to report the results of using hyperspectral in-situ data and satellite images to estimate riverine CDOM from rivers to oceans and Great Lakes. A major research goal is to demonstrate that advancement of hyperspectral and high spatial resolution remote sensing technology is vital to the study of interactive processes between terrestrial ecosystems and aquatic environments. Our research results confirm that hyperspectral remote sensing is effective in extracting riverine CDOM loading. INTRODUCTION Chromophoric dissolved organic matter (CDOM) absorbs ultraviolet and visible light [1]. Due to the tight connection with dissolved organic carbon (DOC), CDOM is often used as a DOC tracer [2-6]. Both DOC and CDOM in nature primarily derive from the litter and decaying of vegetation detritus; they are transported to estuarine and coastal waters through terrestrial runoff and stream flow [7, 8]. DOC has significant implications on our environment and climate change due to its important role in the carbon cycle [6, 9-11]. Studying the concentration and distribution of CDOM in aquatic ecosystems, particularly the estuarine and coastal regions, will greatly improve our understanding of the land-water dynamics of DOC, terrestrial-oceanic carbon cycle, and the impact of anthropogenic activities on water quality. METHODOLOGY A method for the inversion of hyperspectral remote sensing is developed to determine the absorption coefficient for CDOM in river-coastal margins. The algorithm was based on above-surface measurements with a ship-mounted spectroradiometer. Simultaneously to above-water srface, water absorption and attenuation coefficients, CDOM and chlorophyll fluorescence, turbidities and other related water properties were also measured at very high resolution (meters) using in situ, underwater and flow-through (shipboard, pumped) optical sensor. Rather than using a dg 440 (the total absorption coefficient for CDOM and non-algal particles) as an indication of the “concentration” of CDOM in most previous ocean color study, we separate a g 440 (the absorption coefficient for CDOM) from a dg 440 based on two absorption-backscattering relationships. The first is between a d 440 (the absorption coefficient for non-algal particles) and b bp 555 (total particulate backscattering coefficient at wavelength 555 nm) and the second is between a p 440 (the absorption coefficient for total particles) and b bp 555. These two relationships are respectively referred to a d -based and a g -based methods. Consequently, based on Lee’s QAA algorithm, we developed the so-called Extended Quasi-Analytical Algorithm (QAA-E) to decompose a dg 440, using both a d - based and a g -based methods. The absorption- backscattering relationships and the QAA-E are tested using International Ocean Color Coordinating Group (IOCCG) synthetic and in situ data as well as field data from our study site. And then the algorithm was calibrated to estimate CDOM distributions in river plume areas from EO-1 Hyperion satellite images. The algorithm was tested with measurements in river dominated coastal margin: Atchafalaya River and the Mississippi River. The test was also extended to Saginaw Bay of the Lake Huron recently. RESULT AND DISCUSSION The resulted accuracy indicates the a d -based method is relatively better than the a g -based method. The accuracy of CDOM estimation is significantly improved 2040 978-1-4673-1159-5/12/$31.00 ©2012 IEEE IGARSS 2012