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Seasonal Trends and Variability of Temperature, Precipitation, and Diurnal Temperature Range in U.S. Climate Divisions

Sakian, Nicholas A
http://rave.ohiolink.edu/etdc/view?acc_num=osu1440428134

Abstract Details

2015, Master of Science, Ohio State University, Atmospheric Sciences.
Seasonal U.S. climate division data (1895-2014) of temperatures and precipitation in seven chosen divisions are analyzed for trends and patterns of variability and for factors contributing the most to the variability of temperature in each season and division. The divisions are chosen to represent regions of the U.S. that conform to particular patterns of variability of the Palmer Drought Severity Index (PDSI) in summer. Rotated principal component analysis (RPCA) of atmospheric and oceanic teleconnection indices, annual atmospheric CO2 concentrations, and time series of cloud cover and divisionally-averaged precipitation removes intercorrelations between these variables in each region. The orthogonal factors produced from RPCA are used in stepwise multiple linear regression (SMLR) to determine the explainable variance in seasonally-averaged daily maximum and minimum temperatures (Tmax, Tmin) and diurnal temperature range (DTR). Simple linear regression is used to determine rates of change in divisionally-averaged DTR, Tmax, and Tmin in each region and season. The major temperature trends found are accelerated warming of Tmin in most regions and seasons, no decline in spring DTR nationally, and similarities among the four interior/central regions. These regions are characterized by statistically significant long-term (1895-2013) and short-term (1960-2013) decreases in DTR and increases in Tmin, with long-term decreases in annually-averaged Tmax and in summer and autumn seasonally-averaged Tmax. The Northwest, Northeast coastal, and Desert Southwest regions experienced long-term increases in DTR and significant increases in both Tmax and Tmin. Variance within time series of seasonally-averaged temperatures is generally greater during warmer periods. Inconsistency in seasonal precipitation in most regions may be increasing in each region’s wet season. Cloud cover is the factor explaining the most variability in DTR overall among all four seasons in Central Ohio (Ohio Valley region), but precipitation is more important than cloud cover for DTR variability in most other regions. Precipitation and soil moisture are most commonly the primary predictors for summer DTR and Tmax. These two predictors combined explain 32% to 56% of variance in summer DTR in most regions. However, steep warming trends in Tmax and Tmin since 1960 are occurring nationwide despite increasing precipitation trends in most regions. The accelerated rise in atmospheric CO2 began in the 1950s, and the CO2 concentration explains 4% to 19% of variability in temperatures in most cases where it is a significant predictor, at most 36.4%. Teleconnection indices, especially the Arctic Oscillation and the North Atlantic Oscillation, are more important in winter SMLR analyses. Extreme seasonal temperature anomalies in summer and winter are usually associated with extremes in precipitation, cloud cover, or at least one of the teleconnection indices.
Jay Hobgood (Advisor)
Alvaro Montenegro (Committee Member)
Jeffery Rogers (Other)
116 p.
Atmospheric Sciences; Climate Change; Earth
United States climate; climate change; DTR; diurnal temperature range; temperature trends; global warming; CO2; carbon dioxide; teleconnection

Recommended Citations

Citations

  • Sakian, N. A. (2015). Seasonal Trends and Variability of Temperature, Precipitation, and Diurnal Temperature Range in U.S. Climate Divisions [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440428134

    APA Style (7th edition)

  • Sakian, Nicholas. Seasonal Trends and Variability of Temperature, Precipitation, and Diurnal Temperature Range in U.S. Climate Divisions. 2015. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1440428134.

    MLA Style (8th edition)

  • Sakian, Nicholas. "Seasonal Trends and Variability of Temperature, Precipitation, and Diurnal Temperature Range in U.S. Climate Divisions." Master's thesis, Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440428134

    Chicago Manual of Style (17th edition)

osu1440428134
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© 2015, some rights reserved.Creative Commons License Seasonal Trends and Variability of Temperature, Precipitation, and Diurnal Temperature Range in U.S. Climate Divisions by Nicholas A Sakian is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.