Τίτλος:
A note on some uncertainties associated with Thornthwaite's aridity
index introduced by using different potential evapotranspiration methods
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Potential evapotranspiration (PET) is a key parameter for climate
classification and aridity assessment. The widely used UNEP (1992)
classification system is based on the estimation of the aridity index
AI, which requires annual average values of precipitation P and PET. For
the calculation of PET the Thornthwaite's (1948) formula is, in
principle, suggested. Recent studies use more advanced and accurate
methods for PET estimation but apply to AI the same thresholds proposed
by UNEP for aridity classification. This work deals with the
uncertainties introduced by the use of different PET methods in the
estimation of the aridity index AI. Specifically, the Hargreaves-Samani
(HS) method and four of its modifications, three modifications of
Thornthwaite's formula and the equation of Hamon, are evaluated against
the widely used Thornthwaite's original method, by assessing their
impact on the AI. Climatic data as monthly average values of at least 30
years of measurements from 122 stations in the Greek peninsula are used.
Results show that AI is highly affected by the PET method adopted,
resulting thus to changes in climatic classification of a region.
Further, results imply the need for an adjustment of the threshold
values that determine aridity classes according to the method each time
adopted. Therefore, new threshold values for the aridity classes are
developed and presented in this work. The proposed threshold values
cover a range of sites that belong to semi-arid SA, sub-humid SH and
humid H aridity classes of the Greek peninsula.
Συγγραφείς:
Proutsos, Nikolaos D.
Tsiros, Ioannis X.
Nastos, Panagiotis and
Tsaousidis, Alexandros
Περιοδικό:
Atmospheric Research
Εκδότης:
ELSEVIER SCIENCE INC 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA
Λέξεις-κλειδιά:
Aridity index; Potential Evapotranspiration PET; Hargreaves; Samani;
Thornthwaite methods; Hamon; Greece
DOI:
10.1016/j.atmosres.2021.105727
