On Using the Standard Precipitation Index to assess soil moisture status in North Carolina.

The role of soil moisture estimation is shown to have a significant impact on various climatological applications. The Standard Precipitation Index (SPI) and the Palmer Drought Severity Index (PDSI) are compared in three climate divisions in North Carolina. Comparisons of the indices with precipitation anomalies show that SPI represents short time scale precipitation distributions better than PDSI. This contrast also shows a potential for SPI to improve over PDSI as a guide for soil moisture estimations in mesoscale model initializations. The results show that SPI appears to closely represent soil moisture conditions while PDSI only depicts the general long-term trend.