Integrating Remote Sensing Data on Evapotranspiration and Leaf Area Index with Hydrological Modeling: Impacts on Model Performance and Future Predictions

Abstract

Using the Connecticut River basin as an example, this study assesses the extent to which remote sensing data can help improve hydrological modeling and how it may influence projected future hydrological trends. The dynamic leaf area index (LAI) derived from satellite remote sensing was incorporated into the Variable Infiltration Capacity model (VIC) to enable an interannually varying seasonal cycle of vegetation (VICVEG); the evapotranspiration (ET) data based on remote sensing were combined with ET from a default VIC simulation to develop a simple bias-correction algorithm, and the simulation was then repeated with the bias-corrected ET replacing the simulated ET in the model (VICET). VICET performs significantly better in simulating the temporal variability of river discharge at daily, biweekly, monthly, and seasonal time scales, while VICVEG better captures the interannual variability of discharge, particularly in the winter and spring, and shows slight improvements to soil moisture estimates. The methodology of incorporating ET data into VIC as a bias-correction tool also influences the modeled future hydrological trends. Compared to the default VIC, VICET portrays a future characterized by greater drought risk and a stronger decreasing trend of minimum river flows. Integrating remote sensing data with hydrological modeling helps characterize the range of model-related uncertainties and more accurately reconstruct historic river flow estimates, leading to a better understanding and prediction of hydrological response to future climate changes.

Temperature Dependence of Hourly, Daily, and Event-based Precipitation Extremes Over China

“…Historical observations and future predictions from global and regional climate models indicate that both the magnitude and the frequency of extreme precipitation increase obviously 1–5 , while the annual mean precipitation is detected to increase less than extreme precipitation or even decrease 6 , which may cause drought and flood risks 7,8 . Hence, prediction of precipitation, especially for precipitation extremes, is of significant importance to enhance the adaptivity of human beings to climate change.…”

Global warming from 1.5 to 2 °C will lead to increase in precipitation intensity in China

“…At the same time, drought is exacerbated in some regions because of enhanced evapotranspiration (Zhai et al, 2007). The net effect is that intense precipitation and drought will increase in frequency and severity with global warming (Parr et al, 2015). Thus, it is of great importance to project changes in precipitation extremes for a warming future world.…”

Development of an Evapotranspiration Data Assimilation Technique for Streamflow Estimates: A Case Study in a Semi-Arid Region

“…More work on the uncertainty relationship among precipitation, ET and surface runoff are needed in the future. Historic ET data can be used to correct the ET components estimations, which affect surface runoff generation in VIC [18]. The ET components estimations in GSWAT model have little effect on surface runoff generation.…”

“…Remotely sensed evapotranspiration can be used for hydrological model parameter calibration or estimation, which can affect the surface runoff generation [10,12,13,16,17]. Parr et al [18] found that hydrological predictions may be subject to the bias in past ET modeling, leading to substantial uncertainties in the modeled hydrological trend. They replaced the simulated ET components (canopy evaporation, transpiration, bare ground evaporation, canopy sublimation, and surface sublimation) of the VIC model with the bias-corrected ET calculated from a simple bias-correction algorithm and historic remotely sensed ET.…”

“…This procedure can still be considered as a model bias correction method. Understanding historic evapotranspiration trends and high-quality forcing data are prerequisites, because the mass balance is the main constrain for ET components and runoff updating in VIC [18]. Generally, monthly time scale water balance, including ET and streamflow, can be simulated well by well calibrated hydrological models.…”