Environmental Science 7899 – Issues in Environmental Sciences
Watch the live seminar remotely via CarmenConnect
Seminar Chair: Gil Bohrer, bohrer.17@osu.edu
Seminar Coordinators: Michelle Smith, straley.23@osu.edu; Yanting Guo, zhao.1093@osu.edu
Course Requirements
This course is graded S/U. Satisfactory participation in this course includes all of the following:
- Attentive and active participation in lectures and discussion.
- Attendance at all classes, with one excused absence. If you must miss more than one class, see Dr. Bohrer.
- Advance reading for any seminars for which it is required
Trends of Air Temperature, Precipitation and Potential Evapotranspiration in Southeastern United States (SUS) and East-central China (ECC)
By Yiming Zhao
Human beings are increasing emissions of greenhouse gases, inducing the anthropogenic climate change. Climate change influences the air temperature as well as the hydrological cycle globally. In the background of climate change, previous researches indicated different trends of air temperature, precipitation and evapotranspiration in the southeastern United States (SUS) and east-central China (ECC). This study’s objective is to compare the trends of air temperature, precipitation and potential evapotranspiration in 59 the SUS and the ECC, and the impacts of climatic drivers on these two regions. The data for analyzing the trends of air temperature, precipitation and potential evapotranspiration are from 6 stations in 3 states in the SUS and 6 stations in 3 provinces in the ECC.
To analyze the different impacts of large-scale climatic drivers on the air temperature, precipitation and potential evapotranspiration in the SUS and the ECC, 7 climatic drivers were selected to obtain their correlations to the air temperature, precipitation and potential evapotranspiration in these two regions. No significant cooling trend is found in the weather stations selected in the southeastern United States during 1951-2013. Stepwise multiple linear regression (SMLR) models are employed to reveal the impacts of the large-scale climatic drivers on the variance of the monthly air temperature in these two regions. All 7 climatic drivers selected for the regression models are linked to more than 75% of the variance in both the SUS and the ECC. In both regions, the North Pacific Index, the Atlantic Multidecadal Oscillation and the Niño3.4 Index explain most of the variance, in which North Pacific Index contributes to the variance most. The predicted annual air temperature in the SUS also shows no significant trend in cooling during 1950–2013, however, in both the SUS and the ECC, a rapidly increasing trend in predicted annual air temperature is significant (0.041 ºC/yr in the SUS and 0.056 ºC/yr in the ECC, with 95% confidence) over the 40 years between 1974 and 2013.
Scarcely significant trend of annual total precipitation is observed in the weather stations selected in the SUS and the ECC during 1951-2013. The weather stations selected in the ECC are more likely to have increasing potential evapotranspiration trends than those in the SUS during 1949-2013. SMLR models can’t explain most of the variance of the monthly total precipitation in both regions (1.3% in the SUS and 24.5% in the ECC). Conversely, all 7 climatic drivers selected for the regression models are linked to more than 72% of the variance of monthly total potential evapotranspiration in both regions. The North Pacific Index, the Atlantic Multidecadal Oscillation and the Niño3.4 Index explain most of the variance in both regions. The predicted annual total potential evapotranspiration in the SUS during 1950–2014 and ECC during 1951–2014 shows no significant trend, however, a rapidly increasing trend in predicted annual total potential 100 evapotranspiration is significant in both regions (3.975mm/yr in the SUS and 4.312 mm/yr 101 in the ECC, with 95% confidence) during 1974–2013.
Yiming Zhao is a graduate student in ESGP and a member of CMASC. He received his undergraduate degree in agricultural resources and environment in Zhejiang University, China.
