Rainfall Effects
ISWS/CIR-146/80
Circular 146
STATE OF ILLINOIS ILLINOIS INSTITUTE OF NATURAL RESOURCES
Rainfall Prediction-Measurement Systems and Rainfall Design Information for Urban Areas by STANLEY A. CHANGNON, JR., FLOYD A. HUFF, JOHN L. VOGEL, DAVID A. BRUNKOW, and DONALD W. STAGGS
ILLINOIS STATE WATER SURVEY
CHAMPAIGN
1980
-i-
CONTENTS
Page SYSTEM FOR REAL-TIME PREDICTION AND MONITORING OF PRECIPITATION OVER URBAN AREAS INTRODUCTION Components Philosophy 1 1 5 7 7 11 11 12 12
RADAR PRECIPITATION MEASUREMENT Radar System Antenna Transmitter Receiver
Reflectivity Processor Site Selection Horizon Ground Targets ....
15 15 15
Access and Utilities Computers and Programming RAINGAGE NETWORK
Surveil lance Area
Federal Communications Commission License
16
16 16 18 19 20 23 24 19
Types of Precipitation Gages Density Requirements for Radar-Rainfall Systems Mean Precipitation Pattern Analysis Detection and Areal Extent Installation Procedures
Siting
21 ■.
Density Requirements for Hydrologic Design Data
25 25 25
24
Rain Cell Analysis Operational Use
26
-ii-
Page COMMUNICATION SYSTEMS Radar-Raingage Communications Dedicated Land-Line Telemetered Data Link Dial Land-Line 27 27 27 27
Interrogated-Beacon Data Link
27
27 28 30
Radar System to User Communication DATA ANALYSIS AND INTERPRETATION System Analysis and Interpretation Long-Range Prediction Future Expansion of the System HYDROMETEOROLOGICAL PROPERTIES OF CONVECTIVE STORMS Relation Between Point and Areal Mean Rainfall Frequencies Time Between Successive Heavy Storms Introduction
33 35 35
30
34
Antecedent Rainfall Distribution .
36
36
Orientation and Movement of Heavy Storm Heavy Raincell Characteristics
Synoptic Weather Conditions Associated with Heavy Rainstorms ....
40 45
37
44
Temporal Rainfall Distribution Within Storms Spatial Distribution of Storm Rainfall REFERENCES APPENDIX A
48
50
55 62
Circular 146
STATE OF ILLINOIS ILLINOIS INSTITUTE OF NATURAL RESOURCES
Rainfall Prediction-Measurement Systems and Rainfall Design Information for Urban Areas by STANLEY A. CHANGNON, JR., FLOYD A. HUFF, JOHN L. VOGEL, DAVID A. BRUNKOW, and DONALD W. STAGGS
ILLINOIS STATE WATER SURVEY
CHAMPAIGN
1980
-i-
CONTENTS
Page SYSTEM FOR REAL-TIME PREDICTION AND MONITORING OF PRECIPITATION OVER URBAN AREAS INTRODUCTION Components Philosophy 1 1 5 7 7 11 11 12 12
RADAR PRECIPITATION MEASUREMENT Radar System Antenna Transmitter Receiver
Reflectivity Processor Site Selection Horizon Ground Targets ....
15 15 15
Access and Utilities Computers and Programming RAINGAGE NETWORK
Surveil lance Area
Federal Communications Commission License
16
16 16 18 19 20 23 24 19
Types of Precipitation Gages Density Requirements for Radar-Rainfall Systems Mean Precipitation Pattern Analysis Detection and Areal Extent Installation Procedures
Siting
21 ■.
Density Requirements for Hydrologic Design Data
25 25 25
24
Rain Cell Analysis Operational Use
26
-ii-
Page COMMUNICATION SYSTEMS Radar-Raingage Communications Dedicated Land-Line Telemetered Data Link Dial Land-Line 27 27 27 27
Interrogated-Beacon Data Link
27
27 28 30
Radar System to User Communication DATA ANALYSIS AND INTERPRETATION System Analysis and Interpretation Long-Range Prediction Future Expansion of the System HYDROMETEOROLOGICAL PROPERTIES OF CONVECTIVE STORMS Relation Between Point and Areal Mean Rainfall Frequencies Time Between Successive Heavy Storms Introduction
33 35 35
30
34
Antecedent Rainfall Distribution .
36
36
Orientation and Movement of Heavy Storm Heavy Raincell Characteristics
Synoptic Weather Conditions Associated with Heavy Rainstorms ....
40 45
37
44
Temporal Rainfall Distribution Within Storms Spatial Distribution of Storm Rainfall REFERENCES APPENDIX A
48
50
55 62