1982 - 2020 Precipitation and Temperature Climate Trends for Phoenix, Tucson, and Flagstaff Arizona during Monsoon and Atmospheric River Seasons. .

Keywords: Temperature, Precipitation, Trend, Arizona
Abstract Type: Poster Abstract

Abstract

Between the 2010 – 2020 census, Arizona’s population has grown by 11.9%, increasing from around 6,400,000 to 7,500,000 people. This population increase has coincided with more frequent severe droughts, flash floods, forest fires and extreme temperatures. As part of a larger study investigating people’s perceptions of climate change in Arizona, we examine trends in daily precipitation and temperature for the past four decades for the urban areas of Phoenix, Tucson, and Flagstaff using four fine-resolution observed datasets. Since projections of future climate change suggest the potential for a delayed monsoon onset, the two wet seasons in the state, the Monsoon (June – September) and Atmospheric River (AR, November – March), are compared to determine how trends differ by season. Monthly trends are examined to uncover these changes in rainy season timing. We calculate trends in maximum and minimum daily temperatures, precipitation and extreme precipitation indices including consecutive dry days, consecutive wet days, number of wet days, and the highest one and five-day precipitation amounts. For temperature, Arizona showed an increase in maximums (0.25 C/decade) and minimums (1 C/decade) for both seasons. AR temperatures increased at a higher rate with maximums at around ~1 C/decade and minimums at ~0.75 C/decade . For precipitation, Arizona showed a slightly drier AR season overall ( ~ -1.2 mm/decade) with drier conditions in November and March, while the monsoon season also showed minor changes in overall precipitation amounts but a drier August (~ -1 mm/decade) and a wetter July (~1 mm/decade).