Land Use Characteristics of Areas Around the Metro Station in the Old City of Chengdu: A Case Study of Sichuan Gymnasium Station

Taking Sichuan Gymnasium Station as the research object, we explore land use characteristics over time of areas around Sichuan Gymnasium Station in terms of time. We extract the basic information of land use in areas around Sichuan Gymnasium Station in 2005, 2011, and 2016 through Google Earth in order to draw the map of land use status in three time nodes. We then analyze the degree of mixing and equilibrium, intensity of development of land, and land use patterns of areas around Sichuan Gymnasium Station with indexes including the area proportion of land use patterns, information entropy, and degree of equilibrium within a 1,000-m radius centered on the station, so as to reveal the spatial distribution characteristics of land around the station in different time nodes. Through comparative analysis, it is found that the development of rail transit has not significantly contributed to the boom of commerce and the development of the old city of Chengdu. We also analyze land use changes in areas around Sichuan Gymnasium Station in terms of space, and find that land use patterns in areas around commuter stations seem to be more complicated than that of the average station, and land use patterns in areas around Huaxiba Station and Nijiaqiao Station on Line 1, which opened first, are more complicated than that of Moziqiao Station and Yiguanmiao Station on Line 3. The original land use patterns formed in the old city often determine the selection of rail transit routes and rail transit stations. Adaptive stations do not play a decisive role in land use patterns in their surrounding areas, but have some impact on the plot ratio and building height of land for commercial use within the core area of the stations.

Impacts of precipitation variation and soil and water conservation measures on runoff and sediment yield in the Loess Plateau Gully Region, China

The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation analyses were performed on hydrological data(1981–2012) from the Yanwachuan watershed in the Loess Plateau Gully Region to study the evolution characteristics of runoff and sediment yield. A time-series contrasting method also was used to evaluate the effects of precipitation and soil and water conservation(SWC) on runoff and sediment yield. Annual sediment yield declined markedly from 1981 to 2012 although there was no significant change in annual precipitation and annual runoff. Change points of annual runoff and annual sediment yield occurred in 1996 and 1997,respectively. Compared with that in the baseline period(1981–1996), annual runoff and annual sediment yield in the change period(1997–2012)decreased by 17.0% and 76.0%, respectively, but annual precipitation increased by 6.3%. Runoff decreased in the flood season and normal season, but increased in the dry season, while sediment yield significantly declined in the whole study period. The SWC measures contributed significantly to the reduction of annual runoff(137.9%) and annual sediment yield(135%) and were more important than precipitation. Biological measures(forestland and grassland) accounted for 61.04% of total runoff reduction, while engineering measures(terraces and dams) accounted for 102.84% of total sediment yield reduction. Furthermore, SWC measures had positive ecological effects. This study provides a scientific basis for soil erosion control on the Loess Plateau.

Reconstruction of Lu-level cropland areas in the Northern Song Dynasty （AD976-1078）

Based on data on taxed-cropland area and on the number of households in historical documents, a probabilistic model of cropland distribution and a cropland area allocation model were designed and validated. Cropland areas for the years AD976, 997, 1066, and 1078 were estimated at the level of Lu（an administrative region of the Northern Song Dynasty）. The results indicated that（1） the cropland area of the whole study region for AD976, 997, 1066, and 1078 was about 468.27 million mu（a Chinese unit of area, with1 mu=666.7m2）, 495.53 million mu, 697.65 million mu, and 731.94 million mu, respectively. The fractional cropland area（FCA） increased from 10.7% to 16.8%, and the per capita cropland area decreased from 15.7 mu to 8.4 mu.（2） With regard to the cropland spatial pattern, the FCA of the southeast, north, and southwest regions of the Northern Song territory increased by 12.0%, 5.2%, and 1.2%, respectively. The FCA of some regions in the Yangtze River Plain increased to greater than 40%, and the FCA of the North China Plain increased to greater than 20%. However, the FCA of the southwest region（except for the Chengdu Plain） in the Northern Song territory was less than 6%.（3） There were 84.2% Lus whose absolute relative error was smaller than 20% in the mid Northern Song Dynasty. The validation results indicate that our models are reasonable and that the results of reconstruction are credible.