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Geology topics

Xubin Zeng

Publications and source records attributed to Xubin Zeng.

3 recordsLinked to original sources

Climate sensitivity to decadal land cover and land use change across the conterminous United States

Transitions to terrestrial ecosystems attributable to land cover and land use change (LCLUC) and climate change can affect the climate at local to regional scales. However, conclusions from most previous studies do not provide information about local climate effects, and little research has directly quantified how LCLUC intensity within different ecoregions relates to climate variation. In this study, we present an observation-based analysis of climate sensitivity to LCLUC based on decadal LCLUC and climate data in different ecoregions. Our results revealed that variations in land surface temperature and vapor pressure were most sensitive to LCLUC across the conterminous United States, while precipitation was less sensitive. Persistent warming effects were produced from LCLUC in Appalachian and some of the central U.S., High Plains, and northwest ecoregions, but cooling effects were evident in the many southeast, northeast and some Great Lakes and Intermountain West ecoregions. Most of the warming and a few cooling ecoregions were sensitive to LCLUC. Ecoregions with increasing vapor pressure were found across the Great Plains, Intermountain West, and West Coast ecoregions and several of these regions in the Great Plains and West Coast were sensitive to LCLUC. A combination of changes in temperature, precipitation, and vapor pressure was used to characterize climate sensitivity associated with LCLUC forcing, and five major persistent patterns were found in some ecoregions. These findings suggest that climate conditions, especially temperature and vapor pressure, in some ecoregions are sensitive to LCLUC and such change should be better incorporated into regional climate assessments.

Global and Planetary Change

Urban effects on regional climate: a case study in the Phoenix and Tucson ‘sun’ corridor

Land use and land cover change (LULCC) due to urban expansion alter the surface albedo, heat capacity, and thermal conductivity of the surface. Consequently, the energy balance in urban regions is different from that of natural surfaces. To evaluate the changes in regional climate that could arise due to projected urbanization in the Phoenix-Tucson corridor, Arizona, we applied the coupled WRF-NOAH-UCM (which includes a detailed urban radiation scheme) to this region. Land cover changes were represented using land cover data for 2005 and projections to 2050, and historical North American Regional Reanalysis (NARR) data were used to specify the lateral boundary conditions. Results suggest that temperature changes will be well defined, reflecting the urban heat island (UHI) effect within areas experiencing LULCC. Changes in precipitation are less robust, but seem to indicate reductions in precipitation over the mountainous regions northeast of Phoenix and decreased evening precipitation over the newly-urbanized area.

Earth Interactions

The Landscape Evolution Observatory: a large-scale controllable infrastructure to study coupled Earth-surface processes

Zero-order drainage basins, and their constituent hillslopes, are the fundamental geomorphic unit comprising much of Earth's uplands. The convergent topography of these landscapes generates spatially variable substrate and moisture content, facilitating biological diversity and influencing how the landscape filters precipitation and sequesters atmospheric carbon dioxide. In light of these significant ecosystem services, refining our understanding of how these functions are affected by landscape evolution, weather variability, and long-term climate change is imperative. In this paper we introduce the Landscape Evolution Observatory (LEO): a large-scale controllable infrastructure consisting of three replicated artificial landscapes (each 330 m 2 surface area) within the climate-controlled Biosphere 2 facility in Arizona, USA. At LEO, experimental manipulation of rainfall, air temperature, relative humidity, and wind speed are possible at unprecedented scale. The Landscape Evolution Observatory was designed as a community resource to advance understanding of how topography, physical and chemical properties of soil, and biological communities coevolve, and how this coevolution affects water, carbon, and energy cycles at multiple spatial scales. With well-defined boundary conditions and an extensive network of sensors and samplers, LEO enables an iterative scientific approach that includes numerical model development and virtual experimentation, physical experimentation, data analysis, and model refinement. We plan to engage the broader scientific community through public dissemination of data from LEO, collaborative experimental design, and community-based model development.

Arizona