Martin Mitchell

Spatial patterns of land surface phenology relative to monthly climate variations: US Great Plains

We extracted and mapped six land surface phenological metrics including: (1) the peak normalized difference vegetation index (NDVI), (2) peak date, (3) start of season (SOS), (4) end of season (EOS), (5) length of growing season (LOS), and (6) cumulative NDVI from 2000 to 2009 using Moderate-Resolution Imaging Spectroradiometer (MODIS) images covering the United States (US) Great Plains. Their patterns relative to monthly precipitation, maximum temperature, minimum temperature, and dew points were analyzed using multiple linear regression, stepwise selection, and geographically weighted regression (GWR) analysis. Both peak NDVI and cumulative NDVI had similar spatial patterns. Their values decreased along an east to west gradient. Peak date and SOS also showed compatible patterns. The southeastern Great Plains had the earliest SOS, peak date, and the longest LOS, given its warmer temperatures and greater precipitation. Dew points in March and October as well as the maximum temperature in April highly influenced the SOS, while dew point in August was found more influential for EOS and LOS. Precipitation in March and September also affected the total cumulative NDVI. The GWR models performed better than the OLS because the GWR utilized the spatial relationships between the different variables resulting from local level processes. The regression models predicted peak NDVI and cumulative NDVI better than the other phenological indices.

Assessing Forest Fire and Vegetation Recovery in the Black Hills, South Dakota

After 110 years of sustained fire suppression, the 2000 Jasper fire consumed about 33,785 ha (83,500 acres), or 12% of the Black Hills National Forest. We mapped the severity of the Jasper fire using Landsat imagery and then investigated post-fire vegetation regeneration conditions using field data, Quickbird imagery, and regression modeling. We found that fire scar and severity could be delineated and mapped accurately based on remotely sensed and field-acquired data. Results also revealed that vegetative recovery relative to burn severity, topography, and soil factors could be modeled effectively using local geographically weighted regression (GWR). Further regeneration assessment revealed that severely or heavily burned areas were more rapidly re-vegetated with grasses, forbs, and woody shrubs in the short term. The field survey showed that prescribed burns retard crown fires and that after eight years ponderosa pine seedlings have not re-established.

Variation of the Koppen C/D Climate Boundary in the Central United States during the 20th Century

The spatial and temporal variation of the C/D Köppen climate boundary in the central United States is examined for the period 1900 to 1999. Mean January temperature data from the U.S. Historical Climatology Network for 67 sites located between 37°N and 41.5°N latitude and 90°W and 100°W longitude are utilized. The variation of the boundary between the C and D climates (i.e., 26.6°F isoline) is illustrated for the entire 100-year study period and four quarter-century periods, as well as for individual decades (1900s, 1910s, …, 1980s, 1990s). For the quarter-century climatic periods, the latter two (1950 to 1974, 1975 to 1999) had C/D boundaries farther south (implying “colder” winters) compared to the positions for the first two quarter-century periods. The most anomalous feature for the decadal maps is the distinct southerly location of the C/D boundary for the recent decade of the 1970s. Although the C/D boundaries for the decades of the 1980s and 1990s generally are located slightly north of the 100-year overall mean location (implying “warmer” than average winter conditions), several earlier decades (e.g., 1900s, 1920s, 1930s) had even more northerly positions. Therefore, this study does not provide evidence of a trend toward wintertime warming and a northerly migration of the C/D climate boundary within the central United States. [Key words: climate change, climate classification.]

Climate Change: Length of Growing-Season in the U.S. Corn Belt, 1911-2000

Length of growing-season data were obtained from 90 weather stations covering the core of the U.S. Corn Belt from 1911-2000 and analyzed qualitatively and statistically to ascertain if any systematic trends in warming were/are occurring within the context of global warming. We found that the 1920s were statistically cooler and the 1990s warmer. No discernible trend was statistically found throughout the 90-year period. Qualitatively, the onset of the growing season occurred at an earlier date as the 20th century progressed, but was not found statistically significant. Trends regarding termination dates were inconclusive.

Landscapes and Literature: A Look at the Early Twentieth Century Rural South

Abstract This article examines samples of southern literature from the first half of the twentieth century that can be used to understand geographically the rural landscapes of the Coastal Plain from North Carolina through Mississippi. The socioeconomic imprint upon the land, climatic perceptions, and the role of the forest are themes addressed. The advantages and significance of using a literary approach are also discussed.

Land and Water Policies in the Sacramento-San Joaquin Delta

Rivers can serve as regional bonds (Ullman 1951). This concept is illustrated by the role of the Sacramento -- San Joaquin delta as the node of a vast water-distribution system in California. The delta has a series of aqueducts associated with the federal Central Valley Project, which was authorized in 1933, and the California State Water Project, which was authorized in 1959. They constitute the physical means or imprints on the land by which portions of southern California, the Central Valley, and the San Francisco Bay area are connected to the delta to form a huge functional region (Fig. 1). The water-distribution system serves approximately 18 million people and 2.7 million acres of farmland. Important in the evolution of this region was environmental legislation that progressively laid the policy foundations for use of the land and water resources. Other factors are the characteristics of the physical environment and regional economic and political interests. The analysis of this context centers on an examination of state and federal policies for reclamation of wetlands, land drainage, inland navigation, and mining-debris and flood control prior to 1933 and on an assessment of the regional conflict among northern and southern California, the gold-mining counties of the Sierra Nevada, and the agricultural counties of the Sacramento valley. Wetland Reclamation The first major set of policies directly bearing on the delta related to swamp and flooded-land reclamation, which is hereafter referred to as swampland reclamation. At statehood in 1850 California was granted all of the 2.1 million acres of swamp and flooded lands by the federal government on the condition that receipts from land sales be used to build levees and drains for reclamation (United States 1850). Approximately 500,000 acres of those lands were in the delta, then a virtually unsettled and undeveloped wetland. Segregation of swampland from the federal public domain, ownership, and reclamation were the first policy matters about the delta that the state legislature had to address. Resolving those issues was crucial in transforming the delta into one of the leading agricultural areas of the state. Complicating policy formation was the question of whether a centralized or decentralized authority was responsible. That overarching concern stemmed from philosophical differences about the role of government in the republic. The Jeffersonian viewpoint favored decentralized or local-oriented controls, while the Federalist preferred centralized implementation of policies for the good of the population as a whole. The Democratic Party, which generally adopted the Jeffersonian position, dominated in California during the 1850s, and state policies during that decade reflected the decentralized approach (Kelley 1989, 32-37). In 1855 demarcation of swamplands was delegated to the state surveyor general, who worked with county surveyors (California 1855). However, the state had petitioned Congress for federal surveys. In effect, from the 1850s to the early 1870s state and federal surveys were under way concurrently. The state surveyors, who were often county officials, tended to include lands that were sometimes flooded as swamplands, but federal surveyors left such parcels in the public domain. The contested demarcations were resolved by a state law in 1858 that required the state surveyors to accompany their federal counterparts in the field in the hope that disputes would be settled as they arose. In 1871 the secretary of the interior accepted the state survey lines (Thompson 1957, 189-191). From a spatial standpoint California had sought to maximize the area under its jurisdiction. Settlers and landowners tended to favor a state designation because federal preemption law limited the sale of public domain to 160 acres at a price of

Using Mental Map Principles to Interpret American Indian Cartography

1.25 an acre. In contrast, as many as 320 acres of swampland could be purchased from the state for

The Mountain Pine Beetle Epidemic in the Black Hills, South Dakota: The Consequences of Long Term Fire Policy, Climate Change and the Use of Remote Sensing to Enhance Mitigation

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Taiwan and China: A geostrategic reassessment of U.S. policy

Abstract The understanding of maps drawn or significantly influenced by American Indians fosters critical thinking, cultural diversity, and awareness of a much-neglected topic in cartography. Line styles, scale depiction, and the sizing of individual entities are discussed in the context of applying principles from mental maps to American Indian maps and early European maps of North America possessing significant American Indian input.

FOG CLIMATOLOGY OF THE SACRAMENTO URBAN AREA

The recent and intense outbreak (first decade of 2000s) of the mountain pine beetle in the Black Hills of South Dakota and Wyoming, which impacted over 33% of the 1.2 million acre (486,000 ha) Black Hills National Forest, illustrates what can occur when forest management practices intersect with natural climatic oscillations and climate change to create the “perfect storm” in a region where the physical environment sets the stage for a plethora of economic activities ranging from extractive industries to tourism. This study evaluates the potential of WorldView-2 satellite imagery for green-attacked tree detection in the ponderosa pine forest of the Black Hills, USA. It also discusses the consequences of long term fire policy and climate change, and the use of remote sensing technology to enhance mitigation. It was found that the near-infrared one (band 7) of WorldView-2 imagery had the highest influence on the green-attack classification. The Random Forest classification produced the best results when transferred to the independent dataset, whereas the Logistic Regression models consistently yielded the highest accuracies when cross-validated with the training data. Lessons learned include: (1) utilizing recent advances in remote sensing technologies, most notably the use of WorldView-2 data, to assist in more effectively implementing mitigation measures during an epidemic, and (2) implementing pre-emptive thinning strategies; both of which can be applied elsewhere in the American West to more effectively blunt or preclude the consequences of a mountain pine beetle outbreak on an existing ponderosa pine forest.