Impact of Enso on Weather Conditions at Continental United States Military Bases
Abstract
The climatic response to ENSO events is assessed at continental U.S. military bases for fog, Instrument Flight Rule conditions, snow and freezing rain. Forty-five years of monthly data are classified as El Nino (warm phase), El Viejo (cold phase), or Neutral (neither) according to sea surface temperature anomalies in the central equatorial Pacific. The seasonal data are resampled to estimate population distributions for each of 10, three month seasons in an ENSO year. The difference in means between El Nino (El Viejo), and Neutral events are determined. Conditional probabilities (the probability that a three month seasonal mean for El Nino (El Viejo) will exceed the long-term mean plus one standard deviation) are calculated for all 10 seasons for each climate variable. The results indicate that there are fewer occurrences of fog in both El Nino and El Viejo years than Neutral years, with a few exceptions. Given an El Nino year, fewer IFR hours occur across the entire country, however, during El Viejo years more (fewer) IFR hours occur at military bases in the east (west). The frequency of snow during an El Nino year is dependent on location, but during an El Viejo year fewer (more) hours of snow occur in the east (west). Freezing rain events occur so infrequently that the method could only be applied in a few cases. El Viejo years have more freezing rain events than El Nino years, and the mid-West region has the highest probability of freezing rain events during an El Viejo year.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 09, 1996
- Accession Number
- ADA319128
Entities
People
- Shannon R. Sweeny
Organizations
- Florida State University