A critical analysis of bulk precipitation recycling models

Precipitation recycling is the contribution of local land evaporation to the precipitation of a region. The significant local evaporative contribution to rainfall in many continental regions highlights the potential importance of land-atmosphere feedback. This thesis addresses three common assumptions in bulk precipitation recycling models: (1) the use of time-averaged data (2) the neglect of the atmospheric storage term and (3) the well-mixed assumption. Bulk precipitation recycling models have been criticized for their use of monthly mean data in estimating moisture influx, which does not capture the diurnal and synoptic variations important in hydrology. This work uses a method to compute moisture influx using the atmospheric data at the finest time-scale available. Smaller monthly recycling ratio estimates were found when using this new method. Most previous recycling studies are monthly. The atmospheric storage term is added to an earlier recycling model to study the submonthly time-scale. The southwest Amazon region during the wet season is investigated. There the synoptic conditions consist of alternating easterly and westerly regimes of three to fourteen day duration. The resulting recycling ratio spatial patterns are shown to reflect the synoptic circulation patterns.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Fitzmaurice, Jean Anne

Advisor dc:contributor.advisor

• Rafael L. Bras.

• Civil and Environmental Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/39356

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/39356