Potential caveats in land surface model evaluations using the US drought monitor: roles of base periods and drought indicators
The US drought monitor (USDM) has been widely used as an observational reference for evaluating land surface model (LSM) simulation of drought. This study investigates potential caveats in such evaluation when the USDM and LSMs use different base periods and drought indices to identify drought. The...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2021-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ac3f63 |
| _version_ | 1827869678567948288 |
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| author | Hailan Wang Li Xu Mimi Hughes Muthuvel Chelliah David G DeWitt Brian A Fuchs Darren L Jackson |
| author_facet | Hailan Wang Li Xu Mimi Hughes Muthuvel Chelliah David G DeWitt Brian A Fuchs Darren L Jackson |
| author_sort | Hailan Wang |
| collection | DOAJ |
| description | The US drought monitor (USDM) has been widely used as an observational reference for evaluating land surface model (LSM) simulation of drought. This study investigates potential caveats in such evaluation when the USDM and LSMs use different base periods and drought indices to identify drought. The retrospective national water model (NWM) v2.0 simulation (1993–2018) was used to exemplify the evaluation, supplemented by North American land data assimilation system phase 2 (NLDAS-2). Over their common period (2000–2018), in distinct contrast with the USDM which shows high drought occurrence (>50%) in the western half of the continental US (CONUS) and the southeastern US with low occurrence (<30%) elsewhere, the NWM and NLDAS-2 based on soil moisture percentiles (SMPs) consistently show higher drought occurrence (30%–40%) in the central and southeastern US than the rest of the CONUS. Much of the differences between the LSMs and USDM, particularly the strong LSM underestimation of drought occurrence in the western and southeastern US, are not attributed to the LSM deficiencies, but rather the lack of long-term drought in the LSM simulations due to their relatively short lengths. Specifically, the USDM integrates drought indices with century-long periods of record, which enables it to capture both short-term (<6 months) drought and long-term (⩾6 months) drought, whereas the relatively short retrospective simulations of the LSMs allows them to adequately capture short-term drought but not long-term drought. In addition, the USDM integrates many drought indices whereas the NWM results are solely based on the SMP, further adding to the inconsistency. The high occurrence of long-term drought in the western and southeastern US in the USDM is further found to be driven collectively by the post-2000 long-term warm sea surface temperature (SST) trend, cold Pacific decadal oscillation and warm Atlantic multi-decadal oscillation, all of which are typical leading patterns of global SST variability that can induce drought conditions in the western, central, and southeastern US. Our findings highlight the effects of the above caveats and suggest that LSM evaluation should stay qualitative when the caveats are considerable. |
| first_indexed | 2024-03-12T15:47:31Z |
| format | Article |
| id | doaj.art-f90eab8b8ff5417d850b9d0cef5a723c |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:47:31Z |
| publishDate | 2021-01-01 |
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| series | Environmental Research Letters |
| spelling | doaj.art-f90eab8b8ff5417d850b9d0cef5a723c2023-08-09T15:23:20ZengIOP PublishingEnvironmental Research Letters1748-93262021-01-0117101401110.1088/1748-9326/ac3f63Potential caveats in land surface model evaluations using the US drought monitor: roles of base periods and drought indicatorsHailan Wang0https://orcid.org/0000-0003-1041-0233Li Xu1Mimi Hughes2Muthuvel Chelliah3David G DeWitt4Brian A Fuchs5Darren L Jackson6NOAA/NWS Climate Prediction Center , College Park, MD 20740, United States of AmericaNOAA/NWS Climate Prediction Center , College Park, MD 20740, United States of America; Innovim LLC , Greenbelt, MD 20770, United States of AmericaNOAA/ESRL Physical Sciences Laboratory , Boulder, CO 80305, United States of AmericaNOAA/NWS Climate Prediction Center , College Park, MD 20740, United States of AmericaNOAA/NWS Climate Prediction Center , College Park, MD 20740, United States of AmericaNational Drought Mitigation Center , Lincoln, NE 68583, United States of AmericaNOAA/ESRL Physical Sciences Laboratory , Boulder, CO 80305, United States of America; Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, CO 80309, United States of AmericaThe US drought monitor (USDM) has been widely used as an observational reference for evaluating land surface model (LSM) simulation of drought. This study investigates potential caveats in such evaluation when the USDM and LSMs use different base periods and drought indices to identify drought. The retrospective national water model (NWM) v2.0 simulation (1993–2018) was used to exemplify the evaluation, supplemented by North American land data assimilation system phase 2 (NLDAS-2). Over their common period (2000–2018), in distinct contrast with the USDM which shows high drought occurrence (>50%) in the western half of the continental US (CONUS) and the southeastern US with low occurrence (<30%) elsewhere, the NWM and NLDAS-2 based on soil moisture percentiles (SMPs) consistently show higher drought occurrence (30%–40%) in the central and southeastern US than the rest of the CONUS. Much of the differences between the LSMs and USDM, particularly the strong LSM underestimation of drought occurrence in the western and southeastern US, are not attributed to the LSM deficiencies, but rather the lack of long-term drought in the LSM simulations due to their relatively short lengths. Specifically, the USDM integrates drought indices with century-long periods of record, which enables it to capture both short-term (<6 months) drought and long-term (⩾6 months) drought, whereas the relatively short retrospective simulations of the LSMs allows them to adequately capture short-term drought but not long-term drought. In addition, the USDM integrates many drought indices whereas the NWM results are solely based on the SMP, further adding to the inconsistency. The high occurrence of long-term drought in the western and southeastern US in the USDM is further found to be driven collectively by the post-2000 long-term warm sea surface temperature (SST) trend, cold Pacific decadal oscillation and warm Atlantic multi-decadal oscillation, all of which are typical leading patterns of global SST variability that can induce drought conditions in the western, central, and southeastern US. Our findings highlight the effects of the above caveats and suggest that LSM evaluation should stay qualitative when the caveats are considerable.https://doi.org/10.1088/1748-9326/ac3f63US drought monitordrought characteristicsland surface model evaluation |
| spellingShingle | Hailan Wang Li Xu Mimi Hughes Muthuvel Chelliah David G DeWitt Brian A Fuchs Darren L Jackson Potential caveats in land surface model evaluations using the US drought monitor: roles of base periods and drought indicators Environmental Research Letters US drought monitor drought characteristics land surface model evaluation |
| title | Potential caveats in land surface model evaluations using the US drought monitor: roles of base periods and drought indicators |
| title_full | Potential caveats in land surface model evaluations using the US drought monitor: roles of base periods and drought indicators |
| title_fullStr | Potential caveats in land surface model evaluations using the US drought monitor: roles of base periods and drought indicators |
| title_full_unstemmed | Potential caveats in land surface model evaluations using the US drought monitor: roles of base periods and drought indicators |
| title_short | Potential caveats in land surface model evaluations using the US drought monitor: roles of base periods and drought indicators |
| title_sort | potential caveats in land surface model evaluations using the us drought monitor roles of base periods and drought indicators |
| topic | US drought monitor drought characteristics land surface model evaluation |
| url | https://doi.org/10.1088/1748-9326/ac3f63 |
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