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| Titel |
Comparative study of atmospheric water vapor budget associated with precipitation in Central US and eastern Mediterranean |
| VerfasserIn |
A. Zangvil, P. J. Lamb, D. H. Portis, F. Jin, S. Malka |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: 10th EGU Plinius Conference on Mediterranean Storms (2008) ; Nr. 23 (2010-02-16), S.3-9 |
| Datensatznummer |
250015100
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| Publikation (Nr.) |
 copernicus.org/adgeo-23-3-2010.pdf |
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| Zusammenfassung |
Water vapor budget (WVB) analysis is a powerful tool for studying processes
leading to precipitation (P), since the linkages among atmospheric dynamics,
water vapor fields, surface conditions, and P are constrained by the
moisture continuity equation. This paper compares WVB calculations over the
US Midwest (MW), the US Southern Great Plains (SGP), and the eastern
Mediterranean Sea (EM) during their seasons of maximum P. Despite the
inter-regional differences in time of year, size of region, and surface
characteristics, the WVBs over these regions have common features. First,
the change in precipitable water (dPW) is highly correlated with the
moisture flux divergence (MFD) and not evaporation (E), implying that
atmospheric humidity is affected more by the large-scale atmospheric
circulation than land-atmosphere interactions. Second, P is positively
correlated with moisture inflow (IF/A). However, a pronounced difference
exists between the North American and the Mediterranean study regions with
respect to the processes associated with increased P. For the MW and the
SGP, increased P is associated with moisture flux convergence (−MFD) due to
increased IF/A. In contrast, increased P over the EM is not associated with
−MFD, since both the outflow (OF/A) and IF/A increase at similar rates.
Recycling ratio (R) estimates were calculated for each region using an
equation previously developed. The moisture recycling methodology involves
the externally advected versus locally evaporated contributions to P being
expressed in terms of a "bulk" formulation in which IF/A and OF/A are
defined at the boundaries of the study area. Due to its scale dependence, R
cannot be directly compared among the different regions, and a normalization
procedure was developed for this comparative study. Its results suggest the
normalized R ranges between 12-25% for the study regions, with the value
for the oceanic EM being somewhat larger than over the continental MW and
SGP. |
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