Application of remote sensing to hydrology including ground water by R.K. Farnsworth J EC. Barrett ft MJ. Dhanju International Hydrological Programme United Nations Educational, Unesco Scientific and Cultural Organization Paris, 1984 united nations educational, [St! scientific and cultural organization 7. puce de Fomenoy. 7j7oo PARIS September 25, 1985 With the compliments of Director, Division of Water Sciences Please find enclosed the publication requested by letter on 4/9/85, ref.: 35.749/LIB 5^ APPLICATION OF REMOTE SENSING TO HYDROLOGY INCLUDING GROUND WATER by Richard K. Farnsworth Hydrologic Research Laboratory National Weather Service, NOAA United States Eric C. Barrett University of Bristol United Kingdom M. S. Dhanju Space Applications Center Indian Space Research Organization India Edited by R. K. Farnsworth IHP-II project A.1.5 Unesco, Paris, 1984 • • \-\.\ ' • • !\ I iL l'\ . v- • • I *-" v '"^ i- '* — — ^ — ^ _ - -.--- c-^o Q^';.\:'' o •'! ; V W-\ "7i/\ SWrr . • j 7- •• --liTA .'\'":'.^. {'•--) i. :070) 8;4C; il sxt 141/142 -i- PREFACE Although the total amount of water on Earth is generally assumed to have remained virtually constant during recorded history, periods of flood and drought have challenged the intellect of man to have the capacity to control the water resources available to him. Currently, the rapid growth of population, together with the extension of irrigated agriculture and industrial development, are stressing the quantity and quality aspects of the natural system. Because of the increasing problems, man has begun to realize that he can no longer follow a "use and discard" philosophy — either with water resources or any other natural resource. As a result, the need for a consistent policy of rational management of water resources has become evident. Rational water management, however, should be founded upon a thorough understanding of water availability and movement. Thus, as a contribution to the solution of the world's water problems, Unesco, in 1965, began the first worldwide programme of studies of the hydrological cycle — the International Hydrological Decade (IHD). The research programme was comple­ mented by a major effort in the field of hydrological education and train­ ing. The activities undertaken during the Decade proved to be of great interest and value to Member States. By the end of that period a majority of Unesco's Member States had formed IHD National Committees to carry out the relevant national activities and to participate in regional and inter­ national cooperation within the IHD programme. The knowledge of the world's water resources as an independent professional option and facilities for the training of hydrologists had been developed. Conscious of the need to expand upon the efforts initiated during the International Hydrological Decade, and, following the recommendations of Member States, Unesco, in 1975, launched a new long-term intergovernmental programme, the International Hydrological Programme (IHP), to follow the Decade. Although the IHP is basically a scientific and educational programme, Unesco has been aware from the beginning of a need to direct its activities toward the practical solutions of the world's very real water resources problems. Accordingly, and in line with the recommendations of the 1977 United Nations Water Conference, the objectives of the International Hydro- logical Programme have been gradually expanded in order to cover not only hydrological processes considered in interrelationship with the environment and human activities, but also the scientific aspects of multi-purpose utilization and conservation of water resources to meet the needs of eco­ nomic and social development. Thus, while maintaining IHP'8 scientific concept, the objectives have shifted perceptibly towards a multidisciplinary approach to the assessment, planning, and rational management of water resources. As part of Unesco's contribution to the objectives of the IHP, two publication series are issued: "Studies and Reports in Hydrology" and "Technical Papers in Hydrology." In addition to these publications, and in order to expedite exchange of information, some works are issued in the form of Technical Documents. -ii- TABLE OF CONTENTS Page PREFACE i LIST OF FIGURES AND TABLES iv ACRONYMS AND ABBREVIATIONS vi FOREWORD viii 1. INTRODUCTION 1 2. THE NATURE AND PRACTICE OF ENVIRONMENTAL REMOTE SENSING 3 2.1 Remote sensing defined 3 2.2 The physical basis of remote sensing 3 2.3 Remote sensing sensors and platforms 6 2.4 Remote sensing data forms and analysis 7 3. HYDROLOGY AND REMOTE SENSING 14 3.1 Hydrology and hydrological observations 14 3.1.1 The hydrological cycle 14 3.1.2 Hydrological units 14 3.1.3 Hydrological measurements 14 3.1.4 Hydrological regimes 16 3.1.5 Hydrological models 17 3.1.6 Hydrologic applications 17 3.1.6.1 Water resources development 17 3.1.6.2 Water quality 18 3.1.6.3 Hydrological extremes 19 3.1.6.3.1 Floods 19 3.1.6.3.2 Droughts 20 3.1.7 Recommended standards and methods for hydrological measurement s 21 3.1.8 Conclusions 21 3.2 Need for remote sensing methods in hydrology 21 3.3 Perceived expectations 22 3.4 Practical constraints 22 3.4.1 Sampling frequencies ...............22 3.4.2 Expiration of data value with time 22 3.4.3 Conversion of raw data to hydrologic data 24 3.4.4 Data resolution 25 3.4.5 New spectral bands 25 3.4.6 Cloud cover 25 3.4.7 Contrast. 26 3.4.8 Optimal conditions for remote sensing related to time of day or season 26 3.4.9 Ground location 26 3.4.10 Compromises 26 4. REMOTE SENSING APPLICATIONS IN HYDROLOGY 27 4.1 Hydrometeorology 27 4.1.1 Rainfall monitoring 27 4.1.2 The use of radar in rainfall monitoring 27 4.1.3 The use of satellites in rainfall monitoring 29 4.1.3.1 Cloud-indexing techniques 32 -iii- TABLE OF CONTENTS (continued) 4.1.3.2 Life-history techniques 33 4.1.3.3 Integrative approaches 41 4.1.4 Evaporation processes 42 4.2 Surface water hydrology 45 4.2.1 General capabilities. 45 4.2.2 Assessments of surface water storage capacities and contents. • 47 4.2.3 Detection of aquatic vegetation 47 4.2.4 Mapping of snow and ice 47 4.2.5 Watershed definition and planning 49 4.2.6 Infiltration and runoff coefficients 51 4.2.7 Irrigation and water consumption 51 4.2.8 Identification of sources of pollution 53 4.2.9 Assessment of flooded areas and flood plain mapping 55 4.2.10 Temporal variations in basin characteristics 56 4.2.11 Integrated use of remote sensing for water resource management 56 4.3 Hydrogeology and groundwater 56 4.3.1 Surface indicators of groundwater 59 4.3.2 Subsurface indicators of groundwater (geophysical methods) 62 4.4 Operational status of remote sensing in hydrology 63 4.5 Tabular summary of current operational applications 65 4.6 Integrated regional studies 84 5. PRACTICAL CONSIDERATIONS FOR THE USE OF REMOTE SENSING IN HYDROLOGY 86 5.1 Data availability 86 5.1.1 Landsat, Skylab, and NASA remote sensing data 86 5.1.2 METEOSAT (geosynchronous data for Europe and Africa) 88 5.1.3 NOAA, GOES (geosynchronous data for North and South America), and NIMBUS coastal zone scanner (CZCS) 88 5.1.4 Other data 89 5.1.5 Radar data 90 5.2 Data systems and costs 90 5.3 Support facilities 90 5.4 Evaluation of results.......... 93 5.4.1 Comparisons against standards 95 5.5 Project planning 96 5.6 Cost benefit studies 96 5.7 Information, education, and training 98 5.7.1 Information 98 5.7.2 Education and training 101 5.8 Organizational issues 102 6. FUTURE NEEDS AND PROSPECTS 104 6.1 General 104 6.2 Suggested activities for continued development of remote sensing 106 ACKNOWLEDGEMENTS 107 REFERENCES 108 -iv- LIST OF FIGURES AND TABLES Figures Page The electromagnetic spectrum 4 (a) Selected blackbody radiation curves for various temperatures. (b) Comparison of radiant exitance of a real body (e.g., quartz) with that of a blackbody. (c) Use of Planck's Law to assess the total radiant exitance falling between selected wavelengths 5 Orbital characteristics of satellites, and the Earth as a satellite of the Sun 8 Examples of imagery from the NOAA polar-orbiting satellite with the Advanced Very High Resolution Radiometer (AVHRR) 9 Examples of METEOSAT geosynchronous satellite imagery 10 Examples of Indian geosynchronous satellite (INSAT) imagery 11 Example of Land sat imagery 12 Variations in estimates due to differences in sampling rates 23 Relations between relative variability and precipitation type 23 Maximum acceptable mean percent error as a function of temporal and spatial averaging scales. Also estimates of the minimum temporal sampling frequencies (samples per day) required to achieve these accuracies 24 Radar mean error versus density of calibrating rain gage sites (solid lines), and the mean error of hourly subcatchment totals for mean rainfall events in middle latitudes in the absence of radar 30 The Bristol interactive scheme (BIAS) in its latest form 34 A simulation of BIAS procedures on an interactive image processing screen 35 The BIAS "Global Regression" 36 Scofield-Oliver convective storm decision tree method 37 Scofield-Oliver technique—warm top modification 38 Scofield-Oliver winter season technique 39 Scofield-Oliver tropical cyclone technique 40 -v- LIST OF FIGURES AND TABLES (continued) Figures Page 15. Flow chart and table for the estimation of point rainfall from-geosynchronous- satellite-imagery—for-South-America.............41— 16. Preprocessing of satellite and radar data for the "FRONTIERS" plan to use radar and satellite imagery for very short-range precipitation forecasting 42 17. Look-up graphs determined by the TELL-US Method representing three subsequent stages in drying of a test plot 44 18.