Last glacial maximum hydro-climate and cyclone characteristics in the Levant: a regional modelling perspective
Proxy-based hydro-climate reconstructions in the Levant suggest enhanced water availability during the last glacial maximum (LGM) compared to present-day conditions. To date, the governing hypothesis is that additional water availability may be directly linked to increased Cyprus Low frequency and i...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2022-01-01
|
| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ac46ea |
| _version_ | 1797747169415921664 |
|---|---|
| author | Patrick Ludwig Assaf Hochman |
| author_facet | Patrick Ludwig Assaf Hochman |
| author_sort | Patrick Ludwig |
| collection | DOAJ |
| description | Proxy-based hydro-climate reconstructions in the Levant suggest enhanced water availability during the last glacial maximum (LGM) compared to present-day conditions. To date, the governing hypothesis is that additional water availability may be directly linked to increased Cyprus Low frequency and intensity in the region. However, this paradigm has not been tested in a modelling framework. With this aim, we analysed results from a weather type classification algorithm and regional climate simulations. The weather type classification is applied to ERA5 reanalysis data for present-day (1979–2018) and two Paleoclimate Modelling Inter-comparison Project PMIP3/PMIP4 pre-industrial and LGM model runs. Dynamical downscaling of the two models with the regional Weather Research and Forecast model shows that the present hydro-climate can largely be reproduced. Our simulations suggest that both evaporation and precipitation were lower in the LGM compared to pre-industrial conditions, and that their relative changes can thus most likely explain the additional water availability during that time. Indeed, evaporation in the eastern Mediterranean is reduced to a higher degree (∼−33%) as compared to precipitation (∼−20%) during the LGM. Particularly, lower evaporation during LGM summer may have sustained the year-round wetter conditions in the Levant. In addition, we find significant changes in Cyprus Low characteristics for the LGM. The simulated daily precipitation associated with Cyprus Lows is significantly lower than pre-industrial values (reduction of 26%–29%), whereas the wind intensity is stronger (increase of 7%–8%). Finally, a significant increase in Cyprus Low frequency during LGM winter is likely (+22%). Indeed, our findings are in line with a plethora of proxy-based reconstructions, and provide a reinterpretation of the driving mechanism of water availability, i.e. strong changes in evaporation rather than precipitation. This study places projected hydro-climatic drying of the Levant in a long timescale perspective. As such, it improves our understanding of the physical processes influencing the hydrological cycle in this vulnerable region, situated on the border between sub-tropical and mid-latitude climate zones. |
| first_indexed | 2024-03-12T15:47:16Z |
| format | Article |
| id | doaj.art-b3998663ea8d4f57b3d334c0a9b77517 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:47:16Z |
| publishDate | 2022-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-b3998663ea8d4f57b3d334c0a9b775172023-08-09T15:23:23ZengIOP PublishingEnvironmental Research Letters1748-93262022-01-0117101405310.1088/1748-9326/ac46eaLast glacial maximum hydro-climate and cyclone characteristics in the Levant: a regional modelling perspectivePatrick Ludwig0https://orcid.org/0000-0003-3655-7890Assaf Hochman1https://orcid.org/0000-0002-9881-1893Department of Tropospheric Research (IMK-TRO), Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT) , Karlsruhe, GermanyDepartment of Tropospheric Research (IMK-TRO), Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT) , Karlsruhe, Germany; The Freddy and Nadine Hermann Institute of Earth Sciences, The Hebrew University of Jerusalem (HUJI) , Edmond Safra Campus, Givat Ram Jerusalem, IsraelProxy-based hydro-climate reconstructions in the Levant suggest enhanced water availability during the last glacial maximum (LGM) compared to present-day conditions. To date, the governing hypothesis is that additional water availability may be directly linked to increased Cyprus Low frequency and intensity in the region. However, this paradigm has not been tested in a modelling framework. With this aim, we analysed results from a weather type classification algorithm and regional climate simulations. The weather type classification is applied to ERA5 reanalysis data for present-day (1979–2018) and two Paleoclimate Modelling Inter-comparison Project PMIP3/PMIP4 pre-industrial and LGM model runs. Dynamical downscaling of the two models with the regional Weather Research and Forecast model shows that the present hydro-climate can largely be reproduced. Our simulations suggest that both evaporation and precipitation were lower in the LGM compared to pre-industrial conditions, and that their relative changes can thus most likely explain the additional water availability during that time. Indeed, evaporation in the eastern Mediterranean is reduced to a higher degree (∼−33%) as compared to precipitation (∼−20%) during the LGM. Particularly, lower evaporation during LGM summer may have sustained the year-round wetter conditions in the Levant. In addition, we find significant changes in Cyprus Low characteristics for the LGM. The simulated daily precipitation associated with Cyprus Lows is significantly lower than pre-industrial values (reduction of 26%–29%), whereas the wind intensity is stronger (increase of 7%–8%). Finally, a significant increase in Cyprus Low frequency during LGM winter is likely (+22%). Indeed, our findings are in line with a plethora of proxy-based reconstructions, and provide a reinterpretation of the driving mechanism of water availability, i.e. strong changes in evaporation rather than precipitation. This study places projected hydro-climatic drying of the Levant in a long timescale perspective. As such, it improves our understanding of the physical processes influencing the hydrological cycle in this vulnerable region, situated on the border between sub-tropical and mid-latitude climate zones.https://doi.org/10.1088/1748-9326/ac46eaeastern Mediterraneanlast glacial maximumregional climate modellingsynoptic systemshydrological cycleMiddle-East |
| spellingShingle | Patrick Ludwig Assaf Hochman Last glacial maximum hydro-climate and cyclone characteristics in the Levant: a regional modelling perspective Environmental Research Letters eastern Mediterranean last glacial maximum regional climate modelling synoptic systems hydrological cycle Middle-East |
| title | Last glacial maximum hydro-climate and cyclone characteristics in the Levant: a regional modelling perspective |
| title_full | Last glacial maximum hydro-climate and cyclone characteristics in the Levant: a regional modelling perspective |
| title_fullStr | Last glacial maximum hydro-climate and cyclone characteristics in the Levant: a regional modelling perspective |
| title_full_unstemmed | Last glacial maximum hydro-climate and cyclone characteristics in the Levant: a regional modelling perspective |
| title_short | Last glacial maximum hydro-climate and cyclone characteristics in the Levant: a regional modelling perspective |
| title_sort | last glacial maximum hydro climate and cyclone characteristics in the levant a regional modelling perspective |
| topic | eastern Mediterranean last glacial maximum regional climate modelling synoptic systems hydrological cycle Middle-East |
| url | https://doi.org/10.1088/1748-9326/ac46ea |
| work_keys_str_mv | AT patrickludwig lastglacialmaximumhydroclimateandcyclonecharacteristicsinthelevantaregionalmodellingperspective AT assafhochman lastglacialmaximumhydroclimateandcyclonecharacteristicsinthelevantaregionalmodellingperspective |