Farmers’ first rain: investigating dry season rainfall characteristics in the Peruvian Andes
In the Peruvian Andes, the first light rainfalls towards the end of the dry season in August-September are known as pushpa . Softening soils and improving sowing conditions, these rains are crucial for planting dates and agricultural planning. Yet pushpa remains to date unexplored in the literature....
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | Environmental Research Communications |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/2515-7620/ace516 |
| _version_ | 1797772077424443392 |
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| author | Cornelia Klein Emily R Potter Cornelia Zauner Wolfgang Gurgiser Rolando Cruz Encarnación Alejo Cochachín Rapre Fabien Maussion |
| author_facet | Cornelia Klein Emily R Potter Cornelia Zauner Wolfgang Gurgiser Rolando Cruz Encarnación Alejo Cochachín Rapre Fabien Maussion |
| author_sort | Cornelia Klein |
| collection | DOAJ |
| description | In the Peruvian Andes, the first light rainfalls towards the end of the dry season in August-September are known as pushpa . Softening soils and improving sowing conditions, these rains are crucial for planting dates and agricultural planning. Yet pushpa remains to date unexplored in the literature. This study uses observations and convection-permitting model simulations to describe the characteristics of pushpa in the Rio Santa valley (Peru). Comparing an observed pushpa case in August 2018 with a dry and wet event of the same season, we find pushpa to coincide with upper-level westerly winds that are otherwise characteristic for dry periods. These conditions impose an upper-level dry layer that favours small-scale, vertically-capped convection, explaining the low rainfall intensities that are reportedly typical for pushpa . Climatologically, we find 83% of pushpa -type events to occur under westerly winds, dominating in August, when 60% of the modelled spatial rainfall extent is linked to pushpa . Larger, more intense deep-convective events gradually increase alongside more easterly winds in September, causing the relative pushpa cloud coverage to drop to ̃20%. We note high inter-annual and -decadal variability in this balance between pushpa and intense convective rainfall types, with the spatial extent of pushpa rainfall being twice as high during 2000-2009 than for the 2010-2018 decade over the key sowing period. This result may explain farmers’ perception in the Rio Santa valley, who recently reported increased challenges due to delayed but more intense pushpa rains before the rainy season start. We thus conclude that the sowing and germination season is crucially affected by the balance of pushpa -type and deep-convective rain, resulting in a higher probability for late first rains to be more intense. |
| first_indexed | 2024-03-12T21:45:53Z |
| format | Article |
| id | doaj.art-0219128bb31241f1b407b1231dcec800 |
| institution | Directory Open Access Journal |
| issn | 2515-7620 |
| language | English |
| last_indexed | 2024-03-12T21:45:53Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Communications |
| spelling | doaj.art-0219128bb31241f1b407b1231dcec8002023-07-26T11:07:01ZengIOP PublishingEnvironmental Research Communications2515-76202023-01-015707100410.1088/2515-7620/ace516Farmers’ first rain: investigating dry season rainfall characteristics in the Peruvian AndesCornelia Klein0https://orcid.org/0000-0001-6686-0458Emily R Potter1https://orcid.org/0000-0001-5273-1292Cornelia Zauner2Wolfgang Gurgiser3https://orcid.org/0000-0003-1150-344XRolando Cruz Encarnación4https://orcid.org/0000-0001-7166-3053Alejo Cochachín Rapre5Fabien Maussion6https://orcid.org/0000-0002-3211-506XDepartment of Atmospheric and Cryospheric Sciences, University of Innsbruck , Innsbruck, Austria; UK Centre for Ecology and Hydrology , Wallingford, United KingdomDepartment of Atmospheric and Cryospheric Sciences, University of Innsbruck , Innsbruck, AustriaDepartment of Atmospheric and Cryospheric Sciences, University of Innsbruck , Innsbruck, AustriaDepartment of Atmospheric and Cryospheric Sciences, University of Innsbruck , Innsbruck, AustriaAutoridad Nacional del Agua , Unidad de Glaciología y Recursos HÍdricos, Huaraz, PeruAutoridad Nacional del Agua , Unidad de Glaciología y Recursos HÍdricos, Huaraz, PeruDepartment of Atmospheric and Cryospheric Sciences, University of Innsbruck , Innsbruck, AustriaIn the Peruvian Andes, the first light rainfalls towards the end of the dry season in August-September are known as pushpa . Softening soils and improving sowing conditions, these rains are crucial for planting dates and agricultural planning. Yet pushpa remains to date unexplored in the literature. This study uses observations and convection-permitting model simulations to describe the characteristics of pushpa in the Rio Santa valley (Peru). Comparing an observed pushpa case in August 2018 with a dry and wet event of the same season, we find pushpa to coincide with upper-level westerly winds that are otherwise characteristic for dry periods. These conditions impose an upper-level dry layer that favours small-scale, vertically-capped convection, explaining the low rainfall intensities that are reportedly typical for pushpa . Climatologically, we find 83% of pushpa -type events to occur under westerly winds, dominating in August, when 60% of the modelled spatial rainfall extent is linked to pushpa . Larger, more intense deep-convective events gradually increase alongside more easterly winds in September, causing the relative pushpa cloud coverage to drop to ̃20%. We note high inter-annual and -decadal variability in this balance between pushpa and intense convective rainfall types, with the spatial extent of pushpa rainfall being twice as high during 2000-2009 than for the 2010-2018 decade over the key sowing period. This result may explain farmers’ perception in the Rio Santa valley, who recently reported increased challenges due to delayed but more intense pushpa rains before the rainy season start. We thus conclude that the sowing and germination season is crucially affected by the balance of pushpa -type and deep-convective rain, resulting in a higher probability for late first rains to be more intense.https://doi.org/10.1088/2515-7620/ace516dry season rainfallWRFconvection-permittingtropical Andesconvective environmentagriculture |
| spellingShingle | Cornelia Klein Emily R Potter Cornelia Zauner Wolfgang Gurgiser Rolando Cruz Encarnación Alejo Cochachín Rapre Fabien Maussion Farmers’ first rain: investigating dry season rainfall characteristics in the Peruvian Andes Environmental Research Communications dry season rainfall WRF convection-permitting tropical Andes convective environment agriculture |
| title | Farmers’ first rain: investigating dry season rainfall characteristics in the Peruvian Andes |
| title_full | Farmers’ first rain: investigating dry season rainfall characteristics in the Peruvian Andes |
| title_fullStr | Farmers’ first rain: investigating dry season rainfall characteristics in the Peruvian Andes |
| title_full_unstemmed | Farmers’ first rain: investigating dry season rainfall characteristics in the Peruvian Andes |
| title_short | Farmers’ first rain: investigating dry season rainfall characteristics in the Peruvian Andes |
| title_sort | farmers first rain investigating dry season rainfall characteristics in the peruvian andes |
| topic | dry season rainfall WRF convection-permitting tropical Andes convective environment agriculture |
| url | https://doi.org/10.1088/2515-7620/ace516 |
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