The Determination Of Geophysical Parameters From Space

This volume gives a wide ranging overview of current issues in the acquisition and evaluation of geophysical information from space and from the air and is suitable for postgraduate and postdoctoral students as well as established workers in the field. Topics covered include the processing and interpretation of remote sensing data from aircraft and satellites; reflection and emission properties of natural surfaces; use of remote sensing data for coastal and marine environmental studies; pollution monitoring; surface temperature measurements and meteorological measurements. In addition, large parts of the material concerns itself with the various data analysis techniques employed and the accuracy of the results obtained when attempting to make geophysical measurements through the atmosphere.

This publication is designed to provide a practical understanding of methods of parameter estimation and uncertainty analysis. The practical problems covered range from simple processing of time- and space-series data to inversion of potential field, seismic, electrical, and electromagnetic data. The various formulations are reconciled with field data in the numerous examples provided in the book; well-documented computer programmes are also given to show how easy it is to implement inversion algorithms.

The monograph being proposed for the English-speaking research community is concentrated on the atmospheric correction of satellite images as a part of thematic interpretation procedures while processing remote sensing data. For linguistic reasons a large section of the community may have been unaware of the progress made in Russia in this field of science and technology. Meanwhile, Russia was the first country to launch the first artificial satellite in 1957 and to obtain from space for the first time spectra of the Earth's atmosphere in the 1960's. New applications of the radiation transfer theory for the atmosphere underlying surface system appeared first in Russia in the 1970's. Direct and in verse problems of the atmospheric optics were then formulated giving the scientific basis for studies of natural resources from space. Since that time new mathematical treatments for the atmospheric correction procedures have been widely developed in Russia, including both analytical and numerical tech niques to simulate spectral, angular, and spatial distributions of the outgoing radiation in visual and infrared regions. The authors of the book were at the beginning of the scientific approach. A wide range of mathematical im provements to elaborate polinomial approximations for dependencies between atmospheric radiation field and parameters of space surveying was due to the necessity to process satellite images in real time using special software of ex isted computer means for the studies.

In the recent years, space-based observation methods have led to a subst- tially improved understanding of Earth system. Geodesy and geophysics are contributing to this development by measuring the temporal and spatial va- ations of the Earth’s shape, gravity ?eld, and magnetic ?eld, as well as at- sphere density. In the frame of the GermanR&D programmeGEOTECHNO- LOGIEN,researchprojectshavebeen launchedin2002relatedto the satellite missions CHAMP, GRACE and ESA’s planned mission GOCE, to comp- mentary terrestrial and airborne sensor systems and to consistent and stable high-precision global reference systems for satellite and other techniques. In the initial 3-year phase of the research programme (2002-2004), new gravity ?eld models have been computed from CHAMP and GRACE data which outperform previous models in accuracy by up to two orders of m- nitude for the long and medium wavelengths. A special highlight is the - termination of seasonal gravity variations caused by changes in continental water masses. For GOCE, to be launched in 2006, new gravity ?eld analysis methods are under development and integrated into the ESA processing s- tem. 200,000 GPS radio occultation pro?les, observed by CHAMP, have been processed on an operational basis. They represent new and excellent inf- mation on atmospheric refractivity, temperature and water vapor. These new developments require geodetic space techniques (such as VLBI, SLR, LLR, GPS) to be combined and synchronized as if being one global instrument.

Our planet is currently experiencing substantial changes due to natural phen- ena and direct or indirect human interactions. Observations from space are the only means to monitor and quantify these changes on a global and long-term p- spective. Continuous time series of a large set of Earth system parameters are needed in order to better understand the processes causing these changes, as well as their interactions. This knowledge is needed to build comprehensive Earth s- tem models used for analysis and prediction of the changing Earth. Geodesy and geophysics contribute to the understanding of system Earth through the observation of global parameter sets in space and time, such as tectonic motion, Earth surface deformation, sea level changes and gravity, magnetic and atmospheric elds. In the framework of the German geoscience research and development p- gramme GEOTECHNOLOGIEN, research projects related to the theme “Observing the Earth System from Space” have been funded within two consecutive phases since 2002, both covering 3 years. The projects address data analysis and model development using the satellite missions CHAMP, GRACE, GOCE and comp- mentary ground or airborne observations. The results of the rst phase projects have been published in the Springer book, titled “Observation of the Earth System from Space”, edited by Flury, Rummel, Reigber, Rothacher, Boedecker and Schreiber in 2006. The present book, titled “System Earth via Geodetic-Geophysical Space Techniques” summarizes in 40 scienti c papers the results of eight coordinated research projects funded in the second phase of this programme (2005–2008).