Investigating the Relationship Between High-Latitude Dust and Precipitation

Abstract

The effect of dust on precipitation at high latitudes has not been adequately explored as most of this research has been restricted to mid- and low-latitude regions. Even so, at these lower latitudes the relationship between dust and precipitation still has not been distinctly established. The purpose of this study is to act as a starting point for understanding the role dust plays in precipitation processes at high latitudes. Knowledge of the effects dust can have on precipitation will allow for better prediction and forecasting through an improvement of regional and global climate models. In order to investigate this relationship, we looked at instances of high-latitude dust and precipitation amounts specifically in regions of Alaska, Iceland and Patagonia. The precipitation data were separated in terms of days where dust was present, versus absent (binary basis). Most of the precipitation averages were low with the highest precipitation amounts seen only on days without dust. The data were also separated into four specific days surrounding the dust event (4-day basis); the day before the dust event, the day of, one day after and two days after. The day of and one day after were limited to having lower levels of precipitation whereas the day before and two days after exhibited a broader range of precipitation levels, which included the highest amounts. These initial observations indicated more of a negative relationship between the high-latitude dust events and precipitation. Two classifications of precipitation intensity were created and tested for the purpose of this study. After which, correlation analyses (Chi-Square Test, Fisher’s Exact Test and Rank Correlations) and classification modeling (Decision Tree modeling) were applied. The p-values from the correlation analyses were less than 0.05 suggesting that there is likely a statistically significant relationship between the high-latitude dust events and precipitation, and this relationship again appears to be slightly negative. The classification models were able to predict the precipitation amounts for the days surrounding the dust events using the two classifications. However, they were not specifically able to distinguish between each of the categories for the classifications as most of the data were in the lower categories.