Projection of Drought Conditions in the Colorado River Basin: A Study Based on the NARCCAP Regional Climate Models
Location
ECC 216
Event Website
http://water.usu.edu/
Start Date
4-3-2012 4:20 PM
End Date
4-3-2012 4:25 PM
Description
Drought is an extreme climate condition that occurs at different temporal and spatial scales and often results in significant economic, environmental, and social impacts. Such impacts are even larger in semi-arid regions such as the Colorado River Basin (CRB). Based on gridded precipitation and temperature as generated by regional climate models of the North American Regional Climate Change Assessment Program (NARCCAP), the spatial and temporal variability of meteorological drought in the CRB during present and future periods was analyzed; first by computing the Palmer Drought Severity Index (PDSI) and then through the Severity-Duration-Frequency (SDF). Furthermore, a copula-based drought analysis was performed by using bias-corrected monthly precipitation dataset from the NARCCAP regional climate models for the CRB. The spatial-temporal dependence relationships between various drought related variables such as intensity and duration were investigated, and their joint probability distribution was constructed by combining drought margins and their dependence structure. This involved four different classes of bivariate copulas– Archimedean, extreme value, Plackett, and elliptical families. It was observed that the extreme value copula (based on the Gumbel–Hougaard copula) shows a better performance in comparison to the other classes of copulas. The joint distribution obtained from the best performing copula was then employed to determine the conditional return period and to derive drought SDF curves for the CRB. The results of this study suggests that the copula method can be used effectively to derive the drought SDF curves that give strong insight into planning appropriate drought mitigation strategies in the CRB.
Projection of Drought Conditions in the Colorado River Basin: A Study Based on the NARCCAP Regional Climate Models
ECC 216
Drought is an extreme climate condition that occurs at different temporal and spatial scales and often results in significant economic, environmental, and social impacts. Such impacts are even larger in semi-arid regions such as the Colorado River Basin (CRB). Based on gridded precipitation and temperature as generated by regional climate models of the North American Regional Climate Change Assessment Program (NARCCAP), the spatial and temporal variability of meteorological drought in the CRB during present and future periods was analyzed; first by computing the Palmer Drought Severity Index (PDSI) and then through the Severity-Duration-Frequency (SDF). Furthermore, a copula-based drought analysis was performed by using bias-corrected monthly precipitation dataset from the NARCCAP regional climate models for the CRB. The spatial-temporal dependence relationships between various drought related variables such as intensity and duration were investigated, and their joint probability distribution was constructed by combining drought margins and their dependence structure. This involved four different classes of bivariate copulas– Archimedean, extreme value, Plackett, and elliptical families. It was observed that the extreme value copula (based on the Gumbel–Hougaard copula) shows a better performance in comparison to the other classes of copulas. The joint distribution obtained from the best performing copula was then employed to determine the conditional return period and to derive drought SDF curves for the CRB. The results of this study suggests that the copula method can be used effectively to derive the drought SDF curves that give strong insight into planning appropriate drought mitigation strategies in the CRB.
https://digitalcommons.usu.edu/runoff/2012/Posters/20