Studying the Im pact of Large Lake Des ic ca tion on the Ac cu racy of Nu mer i cal De scrip tion of Me te o ro log i cal Fields (a Case Study for the Aral Sea)

Ab stract—De scribed is the im pact of the Aral Sea des ic ca tion on the lo cal cli mate and the im pact of its nu mer i cal pre dic tion in the re gion. Pres ented is the anal y sis of two se ries of nu mer i cal ex per i ments with the WRF-ARW model (nu mer i cal pre dic tion and weather re search) with the spa tial res o lu tion of 5 km and 28 σ-surfaces along the ver ti cal up to the level of 50 hPa for the Aral Sea re gion. In the first se ries of fore casts for Jan u ary and July 2009, un der ly ing sur face pa ram e ters from the MODIS da ta base are used. In these se ries the sea sur face mask cor re sponds to the Aral Sea con fig u ra tion in the 1970s. In an other group of ex per i ments, the char ac ter is tics of the un der ly ing sur face of the Aral Sea area are re placed by the re spec tive char ac ter is tics of the sur round ing land. To study the ef fects of vari a tions of sur face prop er ties, air tem per a ture, hu mid ity, cloud i ness, pre cip i ta tion, and wind are an a lyzed. It is dem on strated that if the Aral Sea is as sumed to be ab sent in the model, this re sults in the sig nif i cant strength en ing of the continentality of re gional cli mate and in the in crease in the fore cast skill scores. The sup po si tion is made that the reg u lar (at least each 3–5 years) up date of global da ta bases with the de scrip tion of un der ly ing sur face prop er ties due to the cli mate change can re sult in the con sid er able in crease in the ac cu racy of nu mer i cal pre dic tion and cli mate change mod el ing.