Passive Microwave Remote Sensing of the Earth

Essential to the understanding of global climate change and improved weather forecasts is the gathering of basic data of variables such as temperature, pressure, wind, and the distribution of water vapor, clouds, and other active constituents. The microwave frequency region plays a special role in the remote sensing of these variables because microwave signals penetrate through clouds and therefore provide capabilities of retrieving the parameters under all weather conditions. New instruments provide unprecedented observations of the Earth's environment and offer many unique opportunities to further improve our understanding of weather and climate changes and to benefit significantly the numerical weather prediction. Knowledge of the satellite instrument in-orbit performances is important for better utilization of satellite data in numerical weather prediction models. The topics covered in this book are the fundamentals of satellite microwave instrument calibration, remote sensing sciences and algorithms, and the applications of satellite microwave observations in weather and climate research. The reader gains a full knowledge of satellite microwave instrument calibration and fundamental remote sensing theory and helpful hints for applying microwave data in research and operations, of particular interest to those involved in meteorology and climate research.

Auteur
Dr. Fuzhong Weng received his PhD degree in 1992 from Department of Atmospheric Science, Colorado State University (CSU), Fort Collins, Colorado, USA. He joined NOAA in 1998 as a physical scientist and then managed the US Joint Center for Satellite Data Assimilation Program (JCSDA) from 2002-2005. He served as the chief of sensor physics branch at NOAA/NESDIS from 2005-2010. From 2011 to 2017, Dr. Weng was appointed as the chief of Satellite Meteorology and Climatology of NOAA/NESDIS/Center for Satellite Applications and Research, JCSDA Senior Scientist and Joint Polar Satellite System (JPSS) Sensor Science Chair. He won a number of awards including the first winner of the 2000 NOAA David Johnson Award for his outstanding contributions to satellite microwave remote sensing fields and the utilization of satellite data in the NWP models, US Department of Commerce Gold Medal Award in 2005 for his achievement in satellite data assimilation, NOAA bronze medal for leading successful NOAA-18 instrument calibration, and NOAA Administrator's Award for developing new and powerful radiative transfer models to assimilate advanced satellite data in 2009 and NOAA Administrator's Award for leadership in developing a state-of-the art satellite instrument health monitoring system enabling corrective actions to extend instrument life. He published over 160 papers in US and other international journals.

Résumé
This book covers the fundamentals of satellite microwave instrument calibration, remote sensing sciences and algorithms, as well as the applications of the satellite microwave observations in weather and climate research.

Contenu

Preface XIII

1 Introduction 1

1.1 A Microwave Radiometer System 1

1.2 Blackbody Emission 3

1.3 Linearized Planck Function 4

1.4 Stokes Vector and Its Transformation 5

1.5 Microwave Spectrum 7

1.6 Spectral Response Function 8

1.7 Microwave Antenna Gain and Distribution Function 10

1.8 Microwave Instrument Scan Geometry 11

1.9 Microwave Data Records and Their Terminology 13

2 Atmospheric Absorption and Scattering 15

2.1 Introduction 15

2.2 Microwave Gaseous Absorption 16

2.2.1 Absorption Line and Shape 16

2.2.2 Oxygen Absorption 18

2.2.3 Water Vapor Absorption 22

2.2.4 Nitrogen and Ozone Absorption 23

2.2.5 Line-by-Line Radiative Transfer Model (LBLRTM) 23

2.2.6 Zeeman Splitting Absorption 24

2.2.7 Parameterized Transmittance Model 28

2.3 Cloud Absorption and Scattering 32

2.3.1 Scattering Parameters 32

2.3.2 Particle Size Distribution 34

2.3.3 Rayleigh Approximation 38

2.3.4 HenyeyGreenstein and Rayleigh Phase Matrix 42

2.4 Summary and Conclusions 44

3 Radiative Transfer Modeling at Microwave Frequencies 45

3.1 Introduction 45

3.2 Radiative Transfer Equation 45

3.3 Vector Discrete-Ordinate Method 47

3.4 Radiance Gradient or Jacobians 53

3.5 Benchmark Tests 55

3.6 The Zeroth-Order Approximation to Radiative Transfer Solution 60

3.7 The First-Order Approximation to Radiative Transfer Solution 62

3.8 Ocean Emissivity Model 62

3.8.1 Ocean Roughness Phenomena 62

3.8.2 Approximation ofWater Dielectric Constant 64

3.8.3 Ocean Roughness Heights and Spectrum 67

3.8.4 Foam Coverage 73

3.8.5 Surface Emissivity Vector 74

3.9 Land Emissivity Model 78

3.9.1 Theoretical Approach for Land Emission 78

3.9.2 Optical Parameters of Vegetation Canopy 81

3.9.3 Optical Parameters of Snow 83

3.9.4 Surface Reflection at Layer Interfaces 85

3.9.5 Soil Dielectric Constant 87

3.9.6 Simulated Surface Emissivity Spectra 87

3.10 Summary and Conclusions 88

4 Microwave Radiance Simulations 91

4.1 Introduction 91

4.2 Fast Radiative Transfer Simulations 92

4.3 Calculations of Antenna Brightness Temperatures 96

4.4 Simulations of ATMS Sounding Channels Using Global Forecast Model Outputs 99

4.5 Simulations of ATMS Sounding Channels Using GPSRO Data 105

4.5.1 Collocation of GPS RO and ATMS Data 105

4.5.2 ATMS Bias with Respect to GPS RO Data 107

4.6 Uses of TRMM-Derived Hydrometeor Data in Radiative Transfer Simulations 109

4.6.1 Collocation of ATMS and TRMM Data 109

4.6.2 ATMS BiasesWith Respect to TRMM-Derived Simulations 112

4.7 Advanced Radiative Transfer Simulations 117

4.8 Summary and Conclusions 120

5 Calibration of Microwave Sounding Instruments 123

5.1 Introduction 123

5.2 Calibration Concept 124

5.3 ATMS Instrument Description 124

5.4 ATMS Radiometric Calibration 128

5.5 Impacts of ATMS Antenna Emission on Two-Point Calibration 133

5.6 Retrieval of Reflector Emissivity Using ATMS Pitch-Over Data 135

5.7 ATMS Noise-Equivalent Difference Temperature (NEDT) 138

5.8 Conversion from Antenna to Sensor Brightness Temperature 143

5.9 Summary and Conclusion 147

6 Detection of Interference Signals at Microwave Frequencies 151

6.1 Introduction 151

6.2 Microwave Imaging Radiometers and Data Sets 152

6.3 Radio-Frequency Interference Signals in Microwave Data 154

6.4 Detection of RFI over Land 155

6.4.1 Double Principal Component Analysis (DPCA) 155

6.4.2 Spectral Difference Method 160

6.5 RFI Detection over Oceans 162 6.6 Summary an...