Key drivers controlling stable isotope variations in daily precipitation of Costa Rica: Caribbean Sea versus Eastern Pacific Ocean moisture sources

QUATERNARY SCIENCE REVIEWS

卷:131

Article

Sanchez-Murillo, R.¹  Birkel, C.²  Welsh, K.^3,4  Esquivel-Hernandez, G.¹  Corrales-Salazar, J.¹  Boll, J.⁵  Brooks, E.³  Roupsard, O.^4,6  Saenz-Rosales, O.¹  Katchan, I.⁷  Soulsby, C.²  Araguas-Araguas, L. J.⁸ 

[1] Natl Univ Costa Rica, Stable Isotope Res Grp, Heredia 863000, Costa Rica

[2] Univ Aberdeen, Northern Rivers Inst, Aberdeen AB24 3UF, Scotland

[3] Univ Idaho, Moscow, ID 83844 USA

[4] Ctr Agron Trop Invest & Ensenanza, Turrialba 30501, Costa Rica

[5] Washington State Univ, Pullman, WA 99164 USA

[6] CIRAD, UMR Ecol Fonct & Biogeochim Sols & Agroecosyst, F-34060 Montpellier, France

[7] Ctr Nacl Alta Tecnol, San Jose 11741200, Costa Rica

[8] IAEA, Vienna Int Ctr, Isotope Hydrol Sect, A-1400 Vienna, Austria

关键词: Costa Rica;    Stable isotopes;    Precipitation;    Air mass back trajectories;    Sounding profiles;   

DOI  :  10.1016/j.quascirev.2015.08.028

来源: Elsevier

【 摘 要 】

Costa Rica is located on the Central American Isthmus, which receives moisture inputs directly from the Caribbean Sea and the Eastern Pacific Ocean. This location includes unique mountainous and lowland microclimates, but only limited knowledge exists about the impact of relief and regional atmospheric circulation patterns on precipitation origin, transport, and isotopic composition. Therefore, the main scope of this project is to identify the key drivers controlling stable isotope variations in daily-scale precipitation of Costa Rica. The monitoring sites comprise three strategic locations across Costa Rica: Heredia (Central Valley), Turrialba (Caribbean slope), and Cali Seco (South Pacific slope). Sporadic dry season rain is mostly related to isolated enriched events ranging from 5.8 parts per thousand to 0.9 parts per thousand delta O-18. By mid-May, the Intertropical Convergence Zone reaches Costa Rica resulting in a notable depletion in isotope ratios (up to 18.5 parts per thousand delta O-18). HYSPLIT air mass back trajectories indicate the strong influence on the origin and transport of precipitation of three main moisture transport mechanisms, the Caribbean Low Level Jet, the Colombian Low Level Jet, and localized convection events. Multiple linear regression models constructed based on Random Forests of surface meteorological information and atmospheric sounding profiles suggest that lifted condensation level and surface relative humidity are the main factors controlling isotopic variations. These findings diverge from the recognized 'amount effect' in monthly composite samples across the tropics. Understanding of stable isotope dynamics in tropical precipitation can be used to a) enhance groundwater modeling efforts in ungauged basins where scarcity of long-term monitoring data drastically limit current and future water resources management, b) improve the reconstruction of paleoclimatic records in the Central American land bridge, c) calibrate and validate regional circulation models. (c) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

Free