Climatological moisture sources for the Western North American Monsoon through a Lagrangian approach: their influence on precipitation intensity
<p>This work examines the origin of atmospheric water vapor arriving to the western North American monsoon (WNAM) region over a 34-year period (1981–2014) using a Lagrangian approach. This methodology computes budgets of evaporation minus precipitation <span class="inline-formula"...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2019-02-01
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| Series: | Earth System Dynamics |
| Online Access: | https://www.earth-syst-dynam.net/10/59/2019/esd-10-59-2019.pdf |
| _version_ | 1828354739537969152 |
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| author | P. Ordoñez R. Nieto L. Gimeno P. Ribera D. Gallego C. A. Ochoa-Moya A. I. Quintanar |
| author_facet | P. Ordoñez R. Nieto L. Gimeno P. Ribera D. Gallego C. A. Ochoa-Moya A. I. Quintanar |
| author_sort | P. Ordoñez |
| collection | DOAJ |
| description | <p>This work examines the origin of atmospheric water
vapor arriving to the western North American monsoon (WNAM) region over a
34-year period (1981–2014) using a Lagrangian approach. This methodology
computes budgets of evaporation minus precipitation <span class="inline-formula">(<i>E</i>−<i>P</i>)</span> by calculating changes in
the specific humidity of thousands of air particles advected into the study
area by the observed winds. The length of the period analyzed (34 years)
allows the method to identify oceanic and terrestrial sources of moisture to the
WNAM region from a climatological perspective.</p>
<p>During the wet season, the WNAM region itself is on average the main
evaporative source, followed by the Gulf of California. However, water vapor
originating from the Caribbean Sea, the Gulf of Mexico, and terrestrial
eastern Mexico is found to influence regional-scale rainfall generation.</p>
<p>Enhanced (reduced) moisture transport from the Caribbean Sea and the Gulf of
Mexico from 4 to 6 days before precipitation events seems to be responsible
for increased (decreased) rainfall intensity on regional scales during the
monsoon peak. Westward propagating mid- to upper-level inverted troughs (IVs)
seem to favor these water vapor fluxes from the east. In particular, a
200 % increase in the moisture flux from the Caribbean Sea to the WNAM
region is found to be followed by the occurrence of heavy
precipitation in the WNAM area a few days later. Low-level troughs off the coast of
northwestern Mexico and upper-level IVs over the Gulf of Mexico are also related
to these extreme rainfall events.</p> |
| first_indexed | 2024-04-14T02:29:43Z |
| format | Article |
| id | doaj.art-3a645560c39844e79c4aac38d0be62ce |
| institution | Directory Open Access Journal |
| issn | 2190-4979 2190-4987 |
| language | English |
| last_indexed | 2024-04-14T02:29:43Z |
| publishDate | 2019-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth System Dynamics |
| spelling | doaj.art-3a645560c39844e79c4aac38d0be62ce2022-12-22T02:17:43ZengCopernicus PublicationsEarth System Dynamics2190-49792190-49872019-02-0110597210.5194/esd-10-59-2019Climatological moisture sources for the Western North American Monsoon through a Lagrangian approach: their influence on precipitation intensityP. Ordoñez0R. Nieto1L. Gimeno2P. Ribera3D. Gallego4C. A. Ochoa-Moya5A. I. Quintanar6Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, 04510, MexicoEnvironmental Physics Laboratory (EphysLab), Universidade de Vigo, Ourense, 32004, SpainEnvironmental Physics Laboratory (EphysLab), Universidade de Vigo, Ourense, 32004, SpainDepartamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Seville, 41013, SpainDepartamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Seville, 41013, SpainCentro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, 04510, MexicoCentro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico<p>This work examines the origin of atmospheric water vapor arriving to the western North American monsoon (WNAM) region over a 34-year period (1981–2014) using a Lagrangian approach. This methodology computes budgets of evaporation minus precipitation <span class="inline-formula">(<i>E</i>−<i>P</i>)</span> by calculating changes in the specific humidity of thousands of air particles advected into the study area by the observed winds. The length of the period analyzed (34 years) allows the method to identify oceanic and terrestrial sources of moisture to the WNAM region from a climatological perspective.</p> <p>During the wet season, the WNAM region itself is on average the main evaporative source, followed by the Gulf of California. However, water vapor originating from the Caribbean Sea, the Gulf of Mexico, and terrestrial eastern Mexico is found to influence regional-scale rainfall generation.</p> <p>Enhanced (reduced) moisture transport from the Caribbean Sea and the Gulf of Mexico from 4 to 6 days before precipitation events seems to be responsible for increased (decreased) rainfall intensity on regional scales during the monsoon peak. Westward propagating mid- to upper-level inverted troughs (IVs) seem to favor these water vapor fluxes from the east. In particular, a 200 % increase in the moisture flux from the Caribbean Sea to the WNAM region is found to be followed by the occurrence of heavy precipitation in the WNAM area a few days later. Low-level troughs off the coast of northwestern Mexico and upper-level IVs over the Gulf of Mexico are also related to these extreme rainfall events.</p>https://www.earth-syst-dynam.net/10/59/2019/esd-10-59-2019.pdf |
| spellingShingle | P. Ordoñez R. Nieto L. Gimeno P. Ribera D. Gallego C. A. Ochoa-Moya A. I. Quintanar Climatological moisture sources for the Western North American Monsoon through a Lagrangian approach: their influence on precipitation intensity Earth System Dynamics |
| title | Climatological moisture sources for the Western North American Monsoon through a Lagrangian approach: their influence on precipitation intensity |
| title_full | Climatological moisture sources for the Western North American Monsoon through a Lagrangian approach: their influence on precipitation intensity |
| title_fullStr | Climatological moisture sources for the Western North American Monsoon through a Lagrangian approach: their influence on precipitation intensity |
| title_full_unstemmed | Climatological moisture sources for the Western North American Monsoon through a Lagrangian approach: their influence on precipitation intensity |
| title_short | Climatological moisture sources for the Western North American Monsoon through a Lagrangian approach: their influence on precipitation intensity |
| title_sort | climatological moisture sources for the western north american monsoon through a lagrangian approach their influence on precipitation intensity |
| url | https://www.earth-syst-dynam.net/10/59/2019/esd-10-59-2019.pdf |
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