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Группа авторов. Congo Basin Hydrology, Climate, and Biogeochemistry
Table of Contents
List of Tables
List of Illustrations
Guide
Pages
Geophysical Monograph Series
Geophysical Monograph 269 - English Version
Congo Basin Hydrology, Climate, and Biogeochemistry. A Foundation for the Future
LIST OF CONTRIBUTORS
PREFACE
REFERENCES
1 Congo Basin Research: Building a Foundation for the Future
ABSTRACT
1.1. INTRODUCTION
1.2. OVERVIEW OF THE CONGO BASIN
1.3. THE HISTORY AND THE FUTURE OF THE CONGO BASIN
1.3.1. Comments from Alain Laraque
1.3.2. Comments from Sharon Nicholson
1.3.3. Comments from Jean‐Marie Kileshye Onema
1.3.4. Comments from Raymond Lumbuenamo
1.4. ESTABLISHING A NEW ERA FOR CONGO RESEARCH
REFERENCES
2 Central African Climate: Advances and Gaps
ABSTRACT
2.1. INTRODUCTION
2.2. RAINBELT MECHANISMS
2.3. CONVECTION
2.4 CLIMATE MODELING
2.5 CONCLUSION
REFERENCES
3 The Rainfall and Convective Regime over Equatorial Africa, with Emphasis on the Congo Basin
ABSTRACT
3.1. INTRODUCTION
3.2. METEOROLOGICAL BACKGROUND
3.3. DATA
3.4. MEAN RAINFALL. 3.4.1. Annual Rainfall
3.4.2. Monthly Rainfall
3.4.3. The Seasonal Cycle
3.4.4. The Diurnal Cycle
3.4.5. Spatial Variability of Rainfall
3.5. INTERANNUAL VARIABILITY
3.6. CONVECTIVE ACTIVITY
3.7. COMPARISON WITH THE AMAZON
3.8. SUMMARY AND CONCLUSIONS. 3.8.1. Controls on the Rainfall Regime
3.8.2. Mean Rainfall and the Seasonal Cycle
3.8.3. Spatial and Temporal Variability
3.8.4. Conclusions
ACKNOWLEDGMENTS
REFERENCES
2 Influence of “Slab‐Ocean” Parameterization in a Regional Climate Model (RegCM4) over Central Africa
ABSTRACT
4.1. INTRODUCTION
4.2. DESCRIPTION OF THE MODEL, EXPERIMENTAL PROTOCOL, DATA, AND METHODOLOGY. 4.2.1. Model Description
The “Slab‐Ocean” Parameterization
4.2.2. Data and Methodology. Data
Methodology
4.3. RESULTS AND DISCUSSIONS. 4.3.1. Average Seasonal Climatology of Temperature and Rainfall. Average Seasonal Temperature Climatology
Average Seasonal Rainfall Climatology
4.3.2. Taylor Diagram
4.3.3. Seasonal Cycles of Temperature and Rainfall
4.3.4. Regional Circulation
4.4. CONCLUSION
ACKNOWLEDGMENTS
REFERENCES
5 Understanding the Influence of Climate Variability on Surface Water Hydrology in the Congo Basin
ABSTRACT
5.1. INTRODUCTION
5.2. MATERIALS AND METHOD. 5.2.1. Terrestrial Water Storage
5.2.2. Surface Water Storage Hydrology. Surface Water Storage
In‐situ River Discharge
5.2.3. Tropical Rainfall Measuring Mission
5.2.4. Sea‐Surface Temperature Products
5.2.5. Standardized Precipitation Evapotranspiration Index
5.2.6. Statistical Analysis and Modeling
5.3. RESULTS. 5.3.1. Characteristics of Extreme Events in the Congo Basin
5.3.2. Surface Water Hydrology of the Congo Basin
Spatial and Temporal Patterns of Land Water Storage
Climate Influence on Surface Water Hydrology
5.4. DISCUSSION AND CONCLUSIONS. 5.4.1. Understanding Drought Variabilities, Intensities, Characteristics and Drivers
5.4.2. Surface Water Hydrology of the Congo Basin and the Role of Climate
ACKNOWLEDGMENTS
REFERENCES
6 Hydroclimatic Dynamics of Upstream Ubangi River at Mobaye, Central African Republic: Comparative Study of the Role of Savannah and Equatorial Forest
ABSTRACT
6.1. INTRODUCTION
6.2. STUDY AREA: UPPER BASIN OF THE UBANGI RIVER AT MOBAYE
6.3. DATA AND METHODS. 6.3.1. Hydropluviometric Data
6.3.2. Break Tests for Hydropluviometric Data
6.3.3. Calculation of River Depletion Coefficients
6.4. RESULTS. 6.4.1. Interannual Evolution of Rainfall and Annual Flows of the Ubangi River at Mobaye
6.4.2. Interannual Evolution of Rainfall and Annual Flows in Sub‐Basins of the Ubangi at Mobaye
6.5. DISCUSSION. 6.5.1. Comparative Interannual Evolution of the Ubangi at Mobaye with the Ubangi River at Bangui
6.5.2. Diversity of Major Climatic Ruptures in the Ubangi Basin at Mobaye
6.5.3. Opposing Roles of Savannah and Forest on the Hydropluviometric Dynamics of the Sub‐Basins of the Ubangi River at Mobaye
6.6. CONCLUSION
ACKNOWLEDGMENTS
REFERENCES
7 Evaluation of the Tropical Rainfall Measuring Mission (TRMM) 3B42 and 3B43 Products Relative to Synoptic Weather Station Observations over Cameroon
ABSTRACT
7.1. INTRODUCTION
7.2. STUDY AREA: AGROCLIMATIC ZONES IN CAMEROON
7.3. DATA. 7.3.1. In Situ Rainfall Observations: National Meteorological and Hydrological Services (NMHS) data
7.3.2. Satellite‐Based Rainfall Estimates: TRMM data sets
7.3.3. Climate Hazards InfraRed Precipitation with Stations (CHIRPS)
7.4. METHODOLOGY FOR TRMM EVALUATION
7.5. RESULTS. 7.5.1. Monthly to Annual Time Scale Rainfall Variability
7.5.2. Daily Station Rainfall
7.6. DISCUSSION
7.7. CONCLUSION
ACKNOWLEDGMENTS
REFERENCES
8 A New Look at Hydrology in the Congo Basin, Based on the Study of Multi‐Decadal Time Series
ABSTRACT
8.1. INTRODUCTION
8.1.1. Research context on the Congo Basin
8.1.2. Presentation of Congo Bassin
8.1.3. Problem and Hypothesis
8.2. DATA AND METHODS. 8.2.1. Available Data
8.2.2. Methodologies Used
8.3. RESULTS AND DISCUSSION
8.3.1. Hydro‐Rainfall Statistical Analysis
8.3.2. Average Hydrological Regimes by Periods of Homogeneous Flows
8.3.3. Hydrological Regime of the Cuvette Centrale
8.4. CONCLUSIONS
ACKNOWLEDGMENTS
REFERENCES
9 Historical Changes in Rainfall Patterns over the Congo Basin and Impacts on Runoff (1903–2010)
ABSTRACT
9.1. INTRODUCTION
9.2. MATERIALS AND METHOD. 9.2.1. Precipitation
9.2.2. River Discharge
9.2.3. Evolutionary Patterns of Rainfall and Discharge
9.2.4. Multi‐Linear Regression Analysis
9.2.5. Linear Rates, Correlations, and Cumulative Departures
9.3. RESULTS. 9.3.1. Historical Changes in Precipitation Patterns Over the Congo Basin. GPCC vs CRU Based Precipitation Estimates
Spatiotemporal Variations and Trends in Precipitation
9.3.2. Rainfall vs River Discharge
9.4. DISCUSSION AND CONCLUSION
ACKNOWLEDGMENTS
REFERENCES
10 Water Budgets and Droughts under Current and Future Conditions in the Congo River Basin
ABSTRACT
10.1. INTRODUCTION
10.2. BACKGROUND. 10.2.1. The Congo Basin
10.2.2. Hydroclimate
10.2.3. Land Cover Change
10.3. METHODS. 10.3.1. Hydrological Models
10.3.2. Drought Index
10.3.3. Climate Models
10.3.4. GRACE Satellite TWSA
10.4. RESULTS AND DISCUSSION. 10.4.1. Model Evaluation and Impacts of Land Cover Changes
10.4.2. Total Water Storage Analysis
10.4.3. Historical Changes in Water Budgets and Drought Occurrences
10.4.4. Impacts of Climate Change on Droughts and Water Budgets
10.4.5. Water Budget Changes
10.5. CONCLUSIONS
ACKNOWLEDGMENTS
REFERENCES
11 Spatiotemporal Variability of Droughts in the Congo River Basin: The Role of Atmospheric Moisture Transport
ABSTRACT
11.1. INTRODUCTION
11.1.1. Study Area
11.2. MATERIAL AND METHODS. 11.2.1. Drought Indices
11.2.2. Flexible Particle Dispersion Model
11.2.3. Statistical Analyses
11.2.4. Data
11.3. RESULTS AND DISCUSSION. 11.3.1. Temporal Evolution of Dry and Wet Conditions
11.3.2. Moisture Contributions to Precipitation Over the CRB
11.4. CONCLUSIONS
ACKNOWLEDGMENTS
REFERENCES
12 Two Decades of Hydrologic Modeling and Predictions in the Congo River Basin: Progress and Prospect for Future Investigations
ABSTRACT
12.1. INTRODUCTION
12.2. UNDERSTANDING HYDROLOGIC PROCESSES IN THE CONGO RIVER BASIN
12.3. DATA AVAILABILITY
12.4. EVALUATION OF HYDROLOGIC MODEL APPLICATIONS IN THE CONGO BASIN
12.5. APPLICATION CASES: PERFORMANCE OF GW‐PITMAN AND WEAP MODELS IN THE CONGO RIVER BASIN. 12.5.1. Model Setup and Calibration Procedure
12.5.2. Calibration Results and Uncertainty Prediction
Calibration Trend and Parameters Variation in the Oubangui Drainage System
Calibration Trend and Parameters Variation in the Sangha Drainage System
Calibration Trend and Parameters Variation in the Kasai Drainage System
Calibration Trend and Parameters Variation in the Lualaba Drainage System
GW‐Pitman Wetland Sub‐model
Reservoir Objects in WEAP Model
Model Simulation in the Bangweulu Wetland System
Model Simulation in Kamalondo Depression
Model Simulation for Lake Tanganyika System
Calibration Trend and Parameters Variation in Lower Lualaba
Calibration Trend and Parameters Variation in Middle Congo Drainage System
12.6. CONCLUSIONS AND PROSPECTS FOR FUTURE INVESTIGATIONS
ACKNOWLEDGMENTS
REFERENCES
13 Sources and Sinks of Water of the Cuvette Centrale Wetlands Using Multiple Remote Sensing Measurements and a Hydrologic Model
ABSTRACT
13.1. INTRODUCTION
13.2. METHODS. 13.2.1. Study Area
13.2.2. Mass Balance Analysis
Water Storages
Precipitation
Evapotranspiration
Upland Runoff
River Exchange
13.3. RESULTS. 13.3.1. Temporal Dynamics of Fluxes
13.4. DISCUSSION AND CONCLUSIONS
REFERENCES
14 Investigating the Role of the Cuvette Centrale in the Hydrology of the Congo River Basin
ABSTRACT
14.1. INTRODUCTION
14.2. MATERIALS AND METHODS. 14.2.1. Study Site
14.2.2. Model Selection
Modified Parameters for the Tropics
Water Balance
Input Data
Model Setup
Model Calibration
Model Assessment
Change in Storage
14.2.3. ENVISAT Altimetry
14.3. RESULTS AND DISCUSSION. 14.3.1. Performance of the Model
ENVISAT Altimetry
14.3.2. Basin Wide Water Balance
14.3.3. Hydrological Responses in the Main Tributaries
14.3.4. Cuvette Centrale Water Balance
14.4. CONCLUSION
ACKNOWLEDGMENTS
REFERENCES
15 Estimation of Bathymetry for Modeling Multi‐thread Channel Hydraulics: Application to the Congo River Middle Reach
ABSTRACT
15.1. INTRODUCTION
15.2. DATA AND METHODS
15.2.1. Estimated Bathymetry Model
15.2.2. Observed Bathymetry Model
15.2.3. Hydraulic Modeling
15.3. RESULTS. 15.3.1. Geometric Validation of EBM
15.3.2. Hydraulic Validation
15.4. DISCUSSION
15.5. CONCLUSIONS
SUPPORTING INFORMATION
S15.1 GAUSSIAN FILTER DETAILS
S15.2 EVALUATION OF RELATIONSHIP BETWEEN DEPTH AND DISTANCE FROM BANK
S15.3 FURTHER DETAILS OF OBSERVED BATHYMETRY MODEL PREPARATION
S15.4 HYDRAULIC MODEL TERRAIN RESOLUTION TEST RESULTS
REFERENCES
16 Reviewing Applications of Remote Sensing Techniques to Hydrologic Research in Sub‐Saharan Africa, with a Special Focus on the Congo Basin
ABSTRACT
16.1. INTRODUCTION
16.2. MONITORING THE HYDROLOGICAL CYCLE
16.2.1. Precipitation
16.2.2. Evapotranspiration
16.2.3. Soil Moisture
16.2.4. Water Storage Change
16.2.5. Reservoir and Lake Storage
16.2.6. Surface Runoff
16.3. RIVER AND FLOODPLAIN HYDRODYNAMICS. 16.3.1. Discharge, River Hydraulic Parameters, and Water Levels
16.3.2. Water Area and Extent Monitoring, including Flood Inundation
16.4. SYNTHESIS AND CONCLUSION
REFERENCES
17 Spatial Hydrology and Applications in the Congo River Basin
ABSTRACT
17.1. INTRODUCTION
17.2. SPATIAL HYDROLOGY. 17.2.1. The SWOT space program to strengthen the monitoring of water resources
17.2.2. The Working Group on Spatial Hydrology
17.3. THE CONGO BASIN HYDROLOGICAL MONITORING PROJECT. 17.3.1. The International Commission of the Congo‐Ubangi‐Sangha River Basin
17.3.2. Spatial hydrology in the Congo River Basin
17.3.3. Virtual stations and perspectives on the Congo River Basin
17.3.4. Transformation of Altitudes into Flows
17.3.5. Applications for Hydropower and Inland Navigation in the Congo River Basin
17.4. CONCLUSION
REFERENCES
18 Monitoring Hydrological Variables from Remote Sensing and Modeling in the Congo River Basin
ABSTRACT
18.1. INTRODUCTION
18.2. DATA SETS AND MODEL SET‐UP. 18.2.1. Monitoring the CRB from Radar Altimetry
18.2.2. Rainfall Estimates from Satellite in the CRB
18.2.3. MGB Model Set‐up. Model Set‐up
Model Calibration
Model Validation
Simulated water levels
Flooded areas
18.3. RATING CURVES AND THEIR APPLICABILITY FOR NRT HYDROLOGICAL MONITORING FROM SPACE
18.3.1. Rating Curves Data set all Over the Basin
18.3.2. NRT Discharges and Depths at Existent VSs
18.3.3. A Priori Discharge and Depth at Newly Monitored Locations
18.4. DISCUSSION AND CONCLUSIONS
ACKNOWLEDGMENTS
S18.1 SATELLITE ALTIMETRY DATABASE VALIDATION
S18.2. MGB MODEL CALIBRATION RESULTS
S18.3. MGB MODEL VALIDATION
REFERENCES
19 Long‐Term Hydrological Variations of the Ogooué River Basin
ABSTRACT
19.1. INTRODUCTION
19.2. GEOGRAPHY OF THE OGOOUÉ RIVER BASIN
19.3. PRECIPITATION OF THE OGOOUÉ RIVER BASIN
19.4. OGOOUÉ RIVER BASIN HYDROGRAPHIC NETWORK. 19.4.1. Main Rivers of the Ogooué River Basin
19.4.2. Lakes and Wetlands in the Ogooué River basin
19.5. DISCHARGE OF THE OGOOUÉ RIVER BASIN
19.6. CARBON FLUXES OF THE OGOOUÉ RIVER
19.7. BRIEF COMPARISON OF CHANGES IN THE OGOOUÉ AND THE CONGO RIVER BASINS
19.8. PAST AND FUTURE MONITORING OF THE OGOOUÉ RIVER BASINS
ACKNOWLEDGMENTS
REFERENCES
20 Fluvial Carbon Dynamics across the Land to Ocean Continuum of Great Tropical Rivers: The Amazon and Congo
ABSTRACT
20.1. INTRODUCTION
20.2. THE REGIONS
20.3. ADVECTIVE FLUXES. 20.3.1 pCO2 Distributions in the Mainstem, Tributaries, and Floodplains
20.3.2. POC Fluxes
20.3.3. DOC Fluxes
20.3.4. Floodplain Exchange
20.4. ORGANIC MATTER SOURCES AND METABOLIC POTENTIAL
20.4.1. OM Composition
20.4.2. Degradation Potential of OM
20.4.3. Deforestation and Agricultural Land‐Use Change
20.5. METABOLISM
20.5.1. Metabolic Rates
20.5.2. Substrates for Metabolism
20.6. GAS EXCHANGE
20.7. THE RIVER‐TO‐OCEAN CONTINUUM
20.7.1. Marine Fate of Riverine CO2
20.7.2. Marine Fate of Organic Matter
20.8. CONCLUSION
ACKNOWLEDGMENTS
REFERENCES
21 Measuring Geomorphological Change on the Congo River Using Century‐Old Navigation Charts
ABSTRACT
21.1 INTRODUCTION
21.2. DATA AND METHODOLOGY. 21.2.1. Study Location
21.2.2. Congo River Navigation Charts
21.2.3. High‐Resolution Satellite Images
21.2.4. Method
21.3. RESULTS AND DISCUSSION
21.4. CONCLUSIONS AND NEXT STEPS
ACKNOWLEDGMENTS
REFERENCES
OTHER CONGO MONOGRAPH PAPERS
22 Site Selection, Design, and Implementation of a Sediment Sampling Program on the Kasai River, a Major Tributary of the Congo River
ABSTRACT
22.1 INTRODUCTION
22.2. MATERIAL AND METHODS. 22.2.1. Sampling Program Conceptual Framework
22.2.2. Study Area
22.2.3. Sampling Site Selection
22.2.4. Ground Truthing and Final Sampling Site Selection
22.2.5. Sampling Site Setup and Installation of Sampling Equipment. Choice of Sampling Equipment
Sampling Site Set Up
Installation of Sampling Equipment. ISCO Suction Tube
The OBS 501 Turbidity Sensor and CR200X Data Logger
Other Installations
22.2.6. Programming of Sampling Equipment
22.2.7. Calibration of Suspended Sediment Concentration Data
Methodology for Cross‐Sectional Sampling at Kutu‐Moke
22.2.8. Monitoring and Evaluation of the Sampling Program
22.3. RESULTS AND DISCUSSION. 22.3.1. Preliminary Data and Results
22.3.2. Challenges and Limitations of the Sampling Program
22.4. CONCLUSIONS
ACKNOWLEDGMENTS
REFERENCES
23 New Measurements of Water Dynamics and Sediment Transport along the Middle Reach of the Congo River and the Kasai Tributary
ABSTRACT
23.1. INTRODUCTION
23.2. STUDY REACH AND RECONNAISSANCE SURVEY
23.3. MATERIALS AND METHODS
23.3.1. ADCP Measurement
23.3.2. Water Surface Elevation
23.3.3. River Bathymetry
23.3.4. Automatic Water Level Loggers
23.3.5. Sediment Sampling
23.4. RESULTS AND DISCUSSION
23.4.1. Hydraulic Characteristics and flow Distribution along the Main River Channel of the Congo Basin during the Low Flow Season
23.4.2. Flow Dynamics along the Congo River Lake Tumba Channel
23.4.3. Water Surface Elevation and Bathymetry Measurement
23.4.4. Sediment Distribution
23.5. CONCLUSION, LESSONS LEARNED AND PERSPECTIVES FOR FUTURE MEASUREMENTS
ACKNOWLEDGMENTS
REFERENCES
24 Towards a Framework of Catchment Classification for Hydrologic Predictions and Water Resources Management in the Ungauged Basin of the Congo River: An a priori Approach
ABSTRACT
24.1. INTRODUCTION
24.2. A CONCEPTUAL FRAMEWORK OF CATCHMENT CLASSIFICATION FOR THE CONGO RIVER BASIN
24.2.1. Landscape Partition and Definition of Catchment Units
24.2.2. Catchment Structure
24.2.3. Catchment Processes and Functional Characteristics
24.2.4. Water Resource Services
24.3. METHODOLOGICAL APPROACH. 24.3.1. Definition of Landscape Units
Natural Break of Topographic Gradients
Inclusion of Anthropogenic Features
Characterization of Water Management Units
24.3.2. Data Availability and Analysis
Estimates of the Basin’s Physical Attributes
Ordination by Principal Component Analysis
Hierarchical Agglomerative Cluster Analysis
24.4. RESULTS AND DISCUSSION
24.4.1. Three‐level Partition of the Landscape Units. Catchment Units Along Topographic Gradients
Concave‐shaped curves
Convex‐shaped curves
S‐shaped curves
Rectilinear‐shaped curves
Socioeconomic and Anthropogenic Systems Units
Water Management Units
24.4.2. Cluster analysis by Hierarchical Agglomerative Clustering
24.5. CONCLUSION AND PERSPECTIVES
ACKNOWLEDGMENTS
REFERENCES
25 The Environmental Issues of the Ubangui Water Transfer Project to Lake Chad
ABSTRACT
25.1. INTRODUCTION
25.2. OVERVIEW OF THE WATER TRANSFER PROJECT FROM UBANGUI TO CHAD. 25.2.1. Project History
25.2.2. The Recent Version of the Project
25.3. CONTROVERSIES OVER THE PROJECT TO TRANSFER THE UBANGUI TO LAKE CHAD
25.3.1. Is Lake Chad Really Disappearing?
25.3.2. What about the Current Water Availability of the Ubangui?
25.4. THE PREDICTABLE POTENTIAL EFFECTS OF THE PROJECT. 25.4.1. The Expected Beneficial Effects of the Project
25.4.2. Adverse Effects Revealed in the Feasibility Studies of the Project
25.4.3. Implementation of a Hydrological Extrapolation method for the Prediction of the Potential Environmental Impacts of the IBWT Project
25.4.4. The Environmental Impacts of the Palambo Dam on the Ubangui Hydrosystem
25.5. CONCLUSION
REFERENCES
26 Variability of Lake Chad: What Hydraulic Management Will Preserve Natural Resources?
ABSTRACT
26.1. INTRODUCTION
26.2. MATERIALS AND METHODS
26.3. RESULTS AND DISCUSSIONS. 26.3.1. Recent Changes in Lake Chad
26.3.2. The Diversity of Resources Exploited in Lake Chad
Fishing Practice
Agricultural Activities
Pastoral Resources
26.4. POSSIBLE IMPACT OF AN INTER‐BASIN TRANSFER: CONGO–LAKE CHAD
26.5. PROPOSAL FOR HYDRAULIC MANAGEMENT TO SUSTAINABLY PRESERVE THE NATURAL RESOURCES OF LAKE CHAD
26.6. CONCLUSION
REFERENCES
27 Multi‐Return Periods, Flood Hazards, and Risk Assessment in the Congo River Basin
ABSTRACT
27.1. INTRODUCTION
27.2. STUDY AREA
27.3. FLOOD RISK ANALYTICAL FRAMEWORK
27.4. DATA AND METHODS
27.4.1. Flood Hazard Data
27.4.2. Socioeconomic Data
27.4.3. Methods. Flood Exposure
Risk Hotspot Assessment
Evaluation Process
27.5. RESULTS. 27.5.1. Hazard Assessment
27.5.2. Regional Risk Analysis and Exposure to Floods
27.5.3. Risk Hotspot Assessment
27.6. DISCUSSION
27.7. CONCLUSION
ACKNOWLEDGMENTS
REFERENCES
28 Putting River Users at the Heart of Hydraulics and Morphology Research in the Congo Basin
ABSTRACT
28.1. INTRODUCTION
28.2. RIVER USERS
28.3. GAPS IN SCIENCE KNOWLEDGE RELATED TO RIVER TRANSPORT AND HYDROPOWER
28.4. DESIGNING AND IMPLEMENTING RIVER RESEARCH WITH USERS AT THE HEART: THE CRuHM PROJECT
28.5. CRuHM PROJECT OUTCOMES
28.6. CONCLUSIONS
ACKNOWLEDGMENTS
REFERENCES
INDEX
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