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1.
ROGER F. AUCH DARRELL E. NAPTON STEVEN KAMBLY THOMAS R. MORELAND JR. KRISTI L. SAYLER 《Geographical review》2012,102(1):53-75
Driving forces facilitate or inhibit land‐use / land‐cover change. Human driving forces include political, economic, cultural, and social attributes that often change across time and space. Remotely sensed imagery provides regional land‐change data for the Northern Piedmont, an ecoregion of the United States that continued to urbanize after 1970 through conversion of agricultural and forest land covers to developed uses. Eight major driving forces facilitated most of the land conversion; other drivers inhibited or slowed change. A synergistic web of drivers may be more important in understanding land change than individual drivers by themselves. 相似文献
2.
Michael J. Keables 《自然地理学》2013,34(4):331-348
Numerous studies have documented that the Pacific/North American (PNA) pattern is the dominant extratropical response to ENSO forcing affecting the circulation over North America. However, the PNA is not the sole pattern that occurs during ENSO events. This study identifies the dominant synoptic circulation patterns and associated temperature and precipitation departures that occur during ENSO winters. Using standardized departures of 500 mbar heights over North America and the North Pacific Ocean, a subjective classification of the anomaly maps for winter months identified as warm ENSO events identifies three basic categories of 500 mbar standardized anomaly patterns: Variations of the PNA pattern, the reverse PNA pattern, and patterns with no PNA signature. Composite standardized anomaly maps of the synoptic categories of 500 mbar heights as well as composites of standardized temperature and precipitation departures for the contiguous United States were constructed. Three variations of the PNA, accounting for nearly half of the ENSO winters, are presented, identifying various configurations of the 500 mbar anomaly field and their effect on precipitation and temperature distribution. Similar composites are presented for reverse PNA and non-PNA winters. [Key words: climatology, climate change, El Nińo/Southern Oscillation, troposphere.] 相似文献