You are here
Search results
(1 - 2 of 2)
- Title
- Regional climate response to land use and land cover change in contiguous United States
- Creator
- Nikolić, Jovanka
- Date
- 2020
- Collection
- Electronic Theses & Dissertations
- Description
-
Future land use and land cover (LULC) pattern in the Contiguous United States (CONUS) is expected to be significantly different from that of the present, and as an important surface forcing for earth's climate system, the potential changes in LULC will contribute to climate change at all scales (local, regional to global). While numerous studies have examined how the earth's climate will respond to the anthropogenic increase of greenhouse gas concentrations in the earth's atmosphere, this...
Show moreFuture land use and land cover (LULC) pattern in the Contiguous United States (CONUS) is expected to be significantly different from that of the present, and as an important surface forcing for earth's climate system, the potential changes in LULC will contribute to climate change at all scales (local, regional to global). While numerous studies have examined how the earth's climate will respond to the anthropogenic increase of greenhouse gas concentrations in the earth's atmosphere, this research aims to quantify the response of several climate variables to the expected LULC change in the CONUS using simulations from a regional climate model. The research is composed of three individual studies. The first study assesses the sensitivity of simulated low-level jet (LLJ) characteristics on changes in LULC pattern. As a prominent weather and climate process responsible for transport of moisture from the Gulf of Mexico northward into central CONUS, LLJ plays an important role in the hydrological cycle and wind energy generation over the Great Plains. Therefore, it is important to quantify the potential changes in jet characteristics, such as jet speed, height and frequency, under the influence of LULC change. The second study investigates the impact of LULC change on frost indices - the dates of last spring frost and first fall frost and the length of frost free seasons. Frost is one of the major factors affecting the growth and development of plants and crop production. Future changes in LULC could make some regions more beneficial, while others more harmful to agricultural practice. Finally, the third study examines the potential impact of the changes in LULC pattern on future wind energy resources. As a zero carbon energy resource, wind energy helps limit greenhouse gasses emissions and mitigate climate change. Knowledge gained on where in the CONUS wind power class would likely to change from unsuitable or marginal to suitable, and vice versa, as a result of LULC change can be useful for future wind farm sitting and for making better informed energy policies.
Show less
- Title
- An observational and numerical case study of the Northerly low-level jet over the Great Plains of the United States
- Creator
- Nikolić, Jovanka
- Date
- 2012
- Collection
- Electronic Theses & Dissertations
- Description
-
Low-level jets (LLJs), streams of fast-moving air in the lower atmosphere, have a strong impact on the weather and climate of the Great Plains of the United States. Southerly LLJs are known to play an important role in transporting moisture and heat from the Gulf of Mexico northward and are primarily responsible for the summertime nocturnal convection in the Great Plains region, whereas Northerly LLJs have been linked to blizzards and large spread of wildfires. While numerous studies have...
Show moreLow-level jets (LLJs), streams of fast-moving air in the lower atmosphere, have a strong impact on the weather and climate of the Great Plains of the United States. Southerly LLJs are known to play an important role in transporting moisture and heat from the Gulf of Mexico northward and are primarily responsible for the summertime nocturnal convection in the Great Plains region, whereas Northerly LLJs have been linked to blizzards and large spread of wildfires. While numerous studies have examined the properties and forcing mechanisms of southerly LLJs, little is known about the formation and characteristics of the NLLJs. In this study, we apply the Weather Research and Forecast (WRF) model to simulate two historical cases of a well-developed NLLJ. The purpose is to improve the understanding of the structure and evolution of NLLJ and the large-scale and local atmospheric environments in which they form. The WRF model is configured with multiple nested grids and is initialized using the North American Regional Reanalysis (NARR). The simulation results are compared with both surface and upper-air observations. Simulations were performed with different model physical parameterizations and process analyses are performed to help identify important factors important for the formation of the NLLJs.
Show less