Effects of storms on microwave brightness temperatures and its application to estimate cloud parameters from AMSU-B [Elektronische Ressource] / von Gang Hong

Informations

• Publié par: universitat_bremen
• Publié le: 01 janvier 2004
• Nombre de lectures: 37
• Langue: English
• Poids de l'ouvrage: 21 Mo

Extrait

Effects of Storms on
Microwave Brightness Temperatures and
its Application to
Estimate Cloud Parameters from AMSU-B
Vom Fachbereich für Physik und Elektrotechnik
der Universität Bremen
zur Erlangung des akademischen Grades eines
Doktor der Naturwissenschaften (Dr.rer.nat.)
genehmigte Dissertation
von
Gang Hong
August 2004To my mother and fatherI am the daughter of Earth and Water,
And the nursling of the Sky;
I pass through the pores of the ocean and shores;
I change, but I cannot die.
For after the rain when with never a stain
The pavilion of Heaven is bare,
And the winds and sunbeams with their convex gleams
Build up the blue dome of air,
I silently laught at my own cenotaph,
And out of the caverns of rain,
Like a child from the womb, like a ghost from the tomb,
I arise and unbuild it again.
Percy Bysshe Shelley
“The Cloud”Contents
Abstract 13
1 Introduction 17
1.1 Clouds in the Climate System 17
1.2 Passive Microwave Remote Sensing of Cloud Ice 18
1.2.1 Influence of Clouds on Microwave Brightness Temperatures 19
1.2.2 Cloud Ice Retrieval Algorithms 21
1.2.3 Influence of Cloud Ice on the Water Vapor Channels around 183.3GHz 22
1.3 Outline of the Work 23
2 Microwave Properties of Atmospheric Constituents and Microwave
Radiative Transfer in Atmosphere 25
2.1 Absorption and Emission by Gases 26
2.1.1 Water Vapor Absorption 27
2.1.2 Oxygen Absorption 28
2.1.3 Total Atmospheric Gaseous Absorption 28
2.2 Extinction by Individual Liquid Water and Ice Particles 30
2.2.1 Mie Scattering 31
2.2.2 Rayleigh Approximation 33
2.2.3 Extinction by Liquid Water Particle 34
2.2.4 by Ice Particle 36
2.3 Volume Extinction by Cloud and Rain 42
2.3.1 Hydrometeor Drop Size Distribution 43
2.3.2 Volume Extinction by Cloud Liquid Water 44
2.3.3 V by Ice 45
2.3.4 Volume Extinction by Rain 46
2.4 Microwave Radiative Transfer 47
2.4.1 Microwave Radiative Transfer Equation 48
2.4.2 VDISORT model 51
2.4.3 RTM model 51
3 Data Collections 53
3.1 AMSU 53
3.2 Aircraft Observations 55
3.2.1 Campaigns 55
3.2.2 Instruments 56
3.2.3 Aircraft Data Used in This Thesis 60
4 Effects of Storms on Microwave Brightness Temperatures:
Observations 63
78 Contents
4.1 Case of February 22, 1993 63
4.1.1 Meteorlogical Situation 65
4.1.2 Radiometric and Radar Signatures 66
4.1.3 Discussion of Observations 69
4.2 Case of August 26, 1998 83
4.2.1 Meteorlogical Situation 83
4.2.2 Radiometric and Radar Signatures 84
4.2.3 Discussion of Observations 88
4.3 Summary of Observations 97
5 Effects of Storms on Microwave Brightness Temperatures:
Simulations 99
5.1 Surface Emissivity 99
5.2 Simulations with A Simple Cloud Model 102
5.2.1 Radiative Transfer Considerations 102
5.2.2 Hydrometeor and Atmospheric Profiles 103
5.2.3 Simulation Results and Discussions 104
5.3 Simulations with Hydrometeor Profiles Derived from Radar 110
5.3.1 Hydrometeor and Atmospheric Profiles 111
5.3.2 Simulation Results and Discussions 114
5.3.3 Effects of Cloud Structure 120
5.4 Simulations Using the GCE Cloud Model 121
5.4.1 Simulations of Convective Squall Line 123
5.4.2 Correlation Between Simulated Brightness Temperatures and Ice
Water Path 125
5.4.3 Influence of Clouds on Brightness Temperatures: Case Studies in
Cross Section 127
5.5 Summary of Simulations 137
6 Sensitivity of Microwave Brightness Temperatures at AMSU-B
Channels to Hydrometeors in Tropical Deep Convective Cloud
System 143
6.1 Cloud Model Data and Radiative Transfer Model 144
6.2 Brightness Temperature Depressions and Sensitivity to Surface Emissivities 146
6.3 Sensitivity to Hydrometeor Water Contents in Deep Convective Cloud 148
6.4 Summary of Sensitivity Analysis 154
7 Applications to Estimate Cloud Parameters Using AMSU-B
Frequencies 155
7.1 Potential to Estimate Canting Angle of Tilted Structure Cloud from
Microwave radiances at 183GHz 155
7.1.1 Cloud Data and Radiative Transfer Model 155
7.1.2 Effect of Cloud Structure on Microwave Radiances at 89–190GHz 156
7.1.3 Estimation of Tilted Structure from Brightness Temperatures 158
7.1.4 Application to an Aircraft Case 159
7.1.5 Conclusion 161
7.2 Detection of Tropical Deep Convective Clouds 161Contents 9
7.2.1 Introduction 161
7.2.2 Detection of Deep Convective Clouds from Aircraft Microwave and
Radar Observations 164
7.2.3 Confirmation and Generalization of the Criteria by Simulations 168
7.2.4 Application to AMSU-B Data 171
7.2.5 Conclusion 178
7.3 Retrieval of Ice Water Path and Content 180
7.3.1 Introduction 180
7.3.2 Ice Water Path Retrieval Method 181
7.3.3 Comparison of IWP and IWC Retrieved from AMSU-B and TRMM
Data 187
7.3.4 Conclusion 193
8 Summary and Outlook 195
8.1 195
8.2 Outlook 196
8.2.1 Effect of Frozen Hydrometeor Density on Microwave Radiances at
AMSU-B 196
8.2.2 Comparing Infrared, Precipitation Radar, and Microwave Methods to
Detect Deep Convective Clouds 197
8.2.3 Deep Convective Cloud Climatology 197
8.2.4 Influence on Water Vapor in TTL of Deep Convective Clouds 197
8.2.5 Improvement of Retrieval Algorithm 198
Appendix 199
A Cases of February 10 and January 25, 1999 201
A.1 Radiometric and Radar Signatures 201
A.2 Discussion of Observations 205
A.2.1 Influence of Ice Scattering on High Frequencies 207