Gehendra Kharel | Oklahoma State University (original) (raw)

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Papers by Gehendra Kharel

JAWRA Journal of the American Water Resources Association, 2015

Terminal lakes are impacted by regional changes in climate. Devils Lake (DL), North Dakota, Unite... more Terminal lakes are impacted by regional changes in climate. Devils Lake (DL), North Dakota, United States (U.S.), is a case in which a prolonged shift in the precipitation pattern resulted in a 10-m water level rise over the past two decades, which cost over one billion U.S. dollars in mitigation. Currently, DL is 1.5 m from an uncontrolled overspill to the nearby Sheyenne River, which could lead to unprecedented environmental, social, and economic costs. Water outlets recently implemented in the lake to slow the water-level rise and prevent an uncontrolled overspill are subject to significant concerns over the introduction of invasive species and downstream water quality. We developed a hydrological model of the DL basin using the soil and water assessment tool and analyzed DL’s overspill probability using an ensemble of statistically downscaled General Circulation Model (GCM) projections of the future climate. The results indicate a significant likelihood (7.3- 20.0%) of overspill in the next few decades in the absence of outlets; some members of the GCM integration ensemble suggest an exceedance probability of over 85.0 and 95.0% for the 2020s and 2050s, respectively. Full capacity outlets radically reduce the probability of DL overspill and are able to partially mitigate the problem by decreasing the average lake level by approximately 1.9 and 1.5 m in the 2020s and 2050s, respectively.

Geocarto International, 2012

The climate of the United States Northern Great Plains region is highly variable. Modelling of ag... more The climate of the United States Northern Great Plains region is highly variable. Modelling of agriculture in this region and similar locations depends on the availability and quality of satellite and ground data for agro-climate variables. We evaluated tropical rainfall measuring mission (TRMM) multi-satellite preparation analysis (TMPA) precipitation, atmospheric infrared sounder (AIRS) surface air temperature, and AIRS relative air humidity (RH). A significant bias was found within the temperature and RH products and no bias but an insufficient rain event detection skill in the precipitation product (probability of detection 0.3). A linear correction of the temperature product removed the bias as well as lowered the root mean square deviation (RMSD). The bias-corrections for RH led to increased RMSD or worse correlation. For precipitation, the correlation between the satellite product and ground data improved if cumulative precipitation or only precipitation during the growing season was used.

ABSTRACT Satellite derived precipitation can be used as supplement and/or replacement to ground d... more ABSTRACT Satellite derived precipitation can be used as supplement and/or replacement to ground data in various applications including modeling and weather forecasting based on its accuracy, reliability and validity. We analyzed Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis (TMPA) 3B42 v.6 Level 3 product (0.25° × 0.25°, 3-hour resolution) against the United States Historical Climatology Network (USHCN) ground data from 98 stations in the Northern Great Plains (NGP) over the period of seven years (2003 to 2009). NGP, comprised of Wyoming, Montana, North Dakota, Minnesota, South Dakota and Nebraska states of the US, is located between the latitudes 41° - 49° N and longitudes 94° - 113.5° E within the TMPA product latitude band (50° NS).The goal of this research was to investigate the performance of TMPA over the NGP region. Results showed that the TMPA daily data has poor rainfall detection ability (POD ~ 0.3), weak correlation with the meteorological data (ρ=0.46) and high root mean square deviation (RMSD = 4.9 mm/day). We also found noticeable seasonal differences in the daily TMPA product performance. It underperformed during cold season (November to March) with weaker correlation (0.25) and worse POD (~ 0.15), as compared to relatively modest correlation (0.47) and POD (~0.30) during warm season (April to October). Our analysis at monthly scale revealed significantly better performance of TMPA with higher correlation (0.82) and lower RMSD (0.72 mm/day). Based on our findings, the TMPA daily data might be a poor replacement to ground data, however, at a monthly scale, TMPA can be used to estimate spatial rainfall distribution in NGP and/or as an input to a stochastic daily weather generator.

The combined effects of climate and land-use change have changed both the hydrology and managemen... more The combined effects of climate and land-use change have changed both the hydrology and management of endorheic watersheds globally. Devils Lake (DL), North Dakota, USA, has risen nearly 10 m since 1991, resulting in a costly, lengthy and litigious water management issue in the region. With more than 1 billion US dollars already spent in mitigation, DL is less than 2 m from its uncontrolled overspill to the nearby Sheyenne River, which could lead to mounting economic, environmental and social costs. While previous studies have generally attributed the changes in the hydrology of DL to the current wet spell, the impacts of land-use changes have not been investigated. Using a hydrological model, here we develop four land-use alternatives driven by market and policy conditions in the DL watershed and investigate their effects on DL hydrology and overspill probability under historic and changed climates. Land-use scenarios under an ensemble of statistically downscaled general circulation model projections indicate a higher overspill risk (7.4-17.0 vs. 0-2 %) under historical climate. Incentivized grass and alfalfa scenarios were able to moderate the hydrological implications to DL under a changed climate, indicating their potential companion roles in DL flood mitigation strategies.

Terminal lakes are impacted by regional changes in climate. Devils Lake (DL), North Dakota, Unite... more Terminal lakes are impacted by regional changes in climate. Devils Lake (DL), North Dakota, United States (U.S.), is a case in which a prolonged shift in the precipitation pattern resulted in a 10-m water level rise over the past two decades, which cost over one billion U.S. dollars in mitigation. Currently, DL is 1.5 m from an uncontrolled overspill to the nearby Sheyenne River, which could lead to unprecedented environmental, social, and economic costs. Water outlets recently implemented in the lake to slow the water-level rise and prevent an uncontrolled overspill are subject to significant concerns over the introduction of invasive species and downstream water quality. We developed a hydrological model of the DL basin using the soil and water assessment tool and analyzed DL’s overspill probability using an ensemble of statistically downscaled General Circulation Model (GCM) projections of the future climate. The results indicate a significant likelihood (7.3-
20.0%) of overspill in the next few decades in the absence of outlets; some members of the GCM integration ensemble suggest an exceedance probability of over 85.0 and 95.0% for the 2020s and 2050s, respectively. Full capacity outlets radically reduce the probability of DL overspill and are able to partially mitigate the problem by decreasing the average lake level by approximately 1.9 and 1.5 m in the 2020s and 2050s, respectively.

Geocarto International, 2012

The climate of the United States Northern Great Plains region is highly variable. Modelling of ag... more The climate of the United States Northern Great Plains region is highly variable. Modelling of agriculture in this region and similar locations depends on the availability and quality of satellite and ground data for agro-climate variables. We evaluated tropical rainfall measuring mission (TRMM) multi-satellite preparation analysis (TMPA) precipitation, atmospheric infrared sounder (AIRS) surface air temperature, and AIRS relative air humidity (RH). A significant bias was found within the temperature and RH products and no bias but an insufficient rain event detection skill in the precipitation product (probability of detection *0.3). A linear correction of the temperature product removed the bias as well as lowered the root mean square deviation (RMSD). The bias-corrections for RH led to increased RMSD or worse correlation. For precipitation, the correlation between the satellite product and ground data improved if cumulative precipitation or only precipitation during the growing season was used.

JAWRA Journal of the American Water Resources Association, 2015

Terminal lakes are impacted by regional changes in climate. Devils Lake (DL), North Dakota, Unite... more Terminal lakes are impacted by regional changes in climate. Devils Lake (DL), North Dakota, United States (U.S.), is a case in which a prolonged shift in the precipitation pattern resulted in a 10-m water level rise over the past two decades, which cost over one billion U.S. dollars in mitigation. Currently, DL is 1.5 m from an uncontrolled overspill to the nearby Sheyenne River, which could lead to unprecedented environmental, social, and economic costs. Water outlets recently implemented in the lake to slow the water-level rise and prevent an uncontrolled overspill are subject to significant concerns over the introduction of invasive species and downstream water quality. We developed a hydrological model of the DL basin using the soil and water assessment tool and analyzed DL’s overspill probability using an ensemble of statistically downscaled General Circulation Model (GCM) projections of the future climate. The results indicate a significant likelihood (7.3- 20.0%) of overspill in the next few decades in the absence of outlets; some members of the GCM integration ensemble suggest an exceedance probability of over 85.0 and 95.0% for the 2020s and 2050s, respectively. Full capacity outlets radically reduce the probability of DL overspill and are able to partially mitigate the problem by decreasing the average lake level by approximately 1.9 and 1.5 m in the 2020s and 2050s, respectively.

Geocarto International, 2012

The climate of the United States Northern Great Plains region is highly variable. Modelling of ag... more The climate of the United States Northern Great Plains region is highly variable. Modelling of agriculture in this region and similar locations depends on the availability and quality of satellite and ground data for agro-climate variables. We evaluated tropical rainfall measuring mission (TRMM) multi-satellite preparation analysis (TMPA) precipitation, atmospheric infrared sounder (AIRS) surface air temperature, and AIRS relative air humidity (RH). A significant bias was found within the temperature and RH products and no bias but an insufficient rain event detection skill in the precipitation product (probability of detection 0.3). A linear correction of the temperature product removed the bias as well as lowered the root mean square deviation (RMSD). The bias-corrections for RH led to increased RMSD or worse correlation. For precipitation, the correlation between the satellite product and ground data improved if cumulative precipitation or only precipitation during the growing season was used.

ABSTRACT Satellite derived precipitation can be used as supplement and/or replacement to ground d... more ABSTRACT Satellite derived precipitation can be used as supplement and/or replacement to ground data in various applications including modeling and weather forecasting based on its accuracy, reliability and validity. We analyzed Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis (TMPA) 3B42 v.6 Level 3 product (0.25° × 0.25°, 3-hour resolution) against the United States Historical Climatology Network (USHCN) ground data from 98 stations in the Northern Great Plains (NGP) over the period of seven years (2003 to 2009). NGP, comprised of Wyoming, Montana, North Dakota, Minnesota, South Dakota and Nebraska states of the US, is located between the latitudes 41° - 49° N and longitudes 94° - 113.5° E within the TMPA product latitude band (50° NS).The goal of this research was to investigate the performance of TMPA over the NGP region. Results showed that the TMPA daily data has poor rainfall detection ability (POD ~ 0.3), weak correlation with the meteorological data (ρ=0.46) and high root mean square deviation (RMSD = 4.9 mm/day). We also found noticeable seasonal differences in the daily TMPA product performance. It underperformed during cold season (November to March) with weaker correlation (0.25) and worse POD (~ 0.15), as compared to relatively modest correlation (0.47) and POD (~0.30) during warm season (April to October). Our analysis at monthly scale revealed significantly better performance of TMPA with higher correlation (0.82) and lower RMSD (0.72 mm/day). Based on our findings, the TMPA daily data might be a poor replacement to ground data, however, at a monthly scale, TMPA can be used to estimate spatial rainfall distribution in NGP and/or as an input to a stochastic daily weather generator.

The combined effects of climate and land-use change have changed both the hydrology and managemen... more The combined effects of climate and land-use change have changed both the hydrology and management of endorheic watersheds globally. Devils Lake (DL), North Dakota, USA, has risen nearly 10 m since 1991, resulting in a costly, lengthy and litigious water management issue in the region. With more than 1 billion US dollars already spent in mitigation, DL is less than 2 m from its uncontrolled overspill to the nearby Sheyenne River, which could lead to mounting economic, environmental and social costs. While previous studies have generally attributed the changes in the hydrology of DL to the current wet spell, the impacts of land-use changes have not been investigated. Using a hydrological model, here we develop four land-use alternatives driven by market and policy conditions in the DL watershed and investigate their effects on DL hydrology and overspill probability under historic and changed climates. Land-use scenarios under an ensemble of statistically downscaled general circulation model projections indicate a higher overspill risk (7.4-17.0 vs. 0-2 %) under historical climate. Incentivized grass and alfalfa scenarios were able to moderate the hydrological implications to DL under a changed climate, indicating their potential companion roles in DL flood mitigation strategies.

Terminal lakes are impacted by regional changes in climate. Devils Lake (DL), North Dakota, Unite... more Terminal lakes are impacted by regional changes in climate. Devils Lake (DL), North Dakota, United States (U.S.), is a case in which a prolonged shift in the precipitation pattern resulted in a 10-m water level rise over the past two decades, which cost over one billion U.S. dollars in mitigation. Currently, DL is 1.5 m from an uncontrolled overspill to the nearby Sheyenne River, which could lead to unprecedented environmental, social, and economic costs. Water outlets recently implemented in the lake to slow the water-level rise and prevent an uncontrolled overspill are subject to significant concerns over the introduction of invasive species and downstream water quality. We developed a hydrological model of the DL basin using the soil and water assessment tool and analyzed DL’s overspill probability using an ensemble of statistically downscaled General Circulation Model (GCM) projections of the future climate. The results indicate a significant likelihood (7.3-
20.0%) of overspill in the next few decades in the absence of outlets; some members of the GCM integration ensemble suggest an exceedance probability of over 85.0 and 95.0% for the 2020s and 2050s, respectively. Full capacity outlets radically reduce the probability of DL overspill and are able to partially mitigate the problem by decreasing the average lake level by approximately 1.9 and 1.5 m in the 2020s and 2050s, respectively.

Geocarto International, 2012

The climate of the United States Northern Great Plains region is highly variable. Modelling of ag... more The climate of the United States Northern Great Plains region is highly variable. Modelling of agriculture in this region and similar locations depends on the availability and quality of satellite and ground data for agro-climate variables. We evaluated tropical rainfall measuring mission (TRMM) multi-satellite preparation analysis (TMPA) precipitation, atmospheric infrared sounder (AIRS) surface air temperature, and AIRS relative air humidity (RH). A significant bias was found within the temperature and RH products and no bias but an insufficient rain event detection skill in the precipitation product (probability of detection *0.3). A linear correction of the temperature product removed the bias as well as lowered the root mean square deviation (RMSD). The bias-corrections for RH led to increased RMSD or worse correlation. For precipitation, the correlation between the satellite product and ground data improved if cumulative precipitation or only precipitation during the growing season was used.