Observation of directional exitance and retrieval of soil and foliage component temperatures: Case studies with bi-angular ATSR radiometric data

Li Jia*, Massimo Menenti, Zhongbo Su, Zhao Liang Li

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

Abstract

A mixture of foliage and soil is thermally heterogeneous, so the radiometric temperature of the mixture depends on view direction. A simple linear mixture model was applied to estimate the component surface temperatures of foliage and soil temperatures. The potential of directional observations in the thermal infrared region for land surface studies is a largely uncharted area of research. The availability of the dual-view Along Track Scanning Radiometer (ATSR) observations led to explore new opportunities in this direction. In the context of studies on heat transfer at heterogeneous land surfaces, multiangular thermal infrared (TIR) observations offer the opportunity of overcoming fundamental difficulties in modeling sparse canopies. Three case studies were performed on the estimation of the component temperatures of foliage and soil. The first one included the use of multi - angular field measurements at view angles of 0°, 23° and 52°. The second and third one were done with directional ATSR observations at view angles of 0° and 53° only. Different models have been proposed in literature to interpret observations of directional exitance: (1) simple geometric (deterministic) models of the system, (2) radiative transfer within a complete canopy, and (3) radiative transfer in an inhomogeneous thick layer of vegetation. Our approach is based on the third modeling concept. A target comprising a mixture of foliage and soil is characterized by the gap fraction, and observed radiance is described as a weighted sum of foliage radiance and soil radiance, with the weights being the gap fraction and its complement, respectively. Ground measurements collected during the HEIFE (China), SPG '97 (Oklahoma) and IMGRASS (China) experiments on land - atmosphere interactions were used to evaluate the estimates of soil and foliage temperature.

Original languageEnglish
Title of host publication IEEE International Geoscience and Remote Sensing Symposium
Place of PublicationToronto
PublisherIEEE
Pages33-35
Number of pages3
ISBN (Print) 0-7803-7536-X
DOIs
Publication statusPublished - 28 Jun 2002
Externally publishedYes
EventIEEE International Geoscience and Remote Sensing Symposium, IGARSS 2002 - Toronto, Canada
Duration: 24 Jun 200228 Jun 2002

Conference

ConferenceIEEE International Geoscience and Remote Sensing Symposium, IGARSS 2002
Abbreviated titleIGARSS 2002
CountryCanada
CityToronto
Period24/06/0228/06/02

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