A Seeding Evidence Index (IES) of Hailstorm Clouds with IAg in the Province of Mendoza (Argentina) Using the C Band Radar and the TITAN System.

PÉREZ, R. C. & MARTÍNEZ, H. H.

Viena, Austria

Congreso; EGU General Assembly - European Geosciences Union; 2005

EGU - European Geosciences Union

EGU05-A-00549;  AS1.08-1WE2P-0060; Geophysical Research Abstracts. When a cell is seeded the measured value of parameters for the C band radar that has changed are the height of the maximun reflectivity (Hzmax) and the 40 dbz zone volume, both increase according to the value of the same cells if it was not seeded. These parameters were used as data to develop a statistical correlation that allows to do an analysis of the seeded effects. The statistical analysis gives a very close agreement, the p value was 0 and the Dubin Watson was 0,387137, less than 1,4. The randomized method is the most accepted by the scientist community for the seeding evaluation of the hailstorm clouds with AgI to fight the hailstone formation. In  most of previous studies, the statistics of considered days with seeded cells, whether there was not hail on the ground, the clouds were treated as black box processes. This process produces physical and dynamics changes in the hail formation, but these processes are not measured or identified. In the present paper we lead this conception aside and we begin doing an evaluation identifying and measuring the changes inside the storm cell. We studied of transparent box. We obtained a quantitative index for these processes, using a C band radar and the TITAN system to measure. The first step to evaluate the efficiency is to find evidence proving that the seeding produces into the cell the changes that the conceptual model affirms. For all the explained reasons the statistical method was the more adapted for our work. We can verify that there exists a narrow relationship between established by the conceptual model and the behavior of the radar parameters selected. When a cell is seeding, the value of the measured parameters of the radar that increased are Hzmax y Vol in respect to the value the same cell would have if it was not seeded. With this parameters, we had developed an index (IES), that allows to measure the seeding evidence of hailstorm clouds with AgI. For our objectives we used data of the last five operative seasons. The IES obtained for the Province of Mendoza (Argentina) is: IES = 0,0346 Hzmax + 0,000018 Vol In synthesis, the achievements we obtained were: 1-  A functional relationship to IES for Mendoza. 2- We can validate the conceptual model of seeding of the hailstorm clouds with AgI; correlating the measurements of the radar parameters with the dynamic and physic changes that the seeding produces into the cell. 3. We found an index of the seeding evidence that can be used as another tool for seeding operations.