Study on the spatial-temporal differences and evolution of ecological security in the typical area of the Loess Plateau.

The development and utilization of energy in the Loess Plateau has caused a wide range of ecological security issues, and Yan'an has become a typical area for ecological security research on the Loess Plateau. Ecological security evaluation research can provide data support and scientific reference value for the sustainable development, which is of great significance to the overall social and economic development of the region. In this study, the pressure-state-response (PSR) model was used to establish the evaluation index system in the evaluation of ecological security in Yan'an region (YAR), then the fuzzy analytic hierarchy process (FAHP) was used to determine the internal index weight of each element, and finally the ecological security index value (ESI) was calculated.

Sunshine duration reconstruction in the southeastern Tibetan Plateau based on tree-ring width and its relationship to volcanic eruptions.

Sunshine is as essential as temperature and precipitation for tree growth, but sunshine duration reconstructions based on tree rings have not yet been conducted in China. In this study, we presented a 497-year sunshine duration reconstruction for the southeastern Tibetan Plateau using a width chronology of Abies forrestii from the central Hengduan Mountains. The reconstruction accounted for 53.

Recent enhancement of central Pacific El Niño variability relative to last eight centuries.

The far-reaching impacts of central Pacific El Niño events on global climate differ appreciably from those associated with eastern Pacific El Niño events. Central Pacific El Niño events may become more frequent in coming decades as atmospheric greenhouse gas concentrations rise, but the instrumental record of central Pacific sea-surface temperatures is too short to detect potential trends. Here we present an annually resolved reconstruction of NIÑO4 sea-surface temperature, located in the central equatorial Pacific, based on oxygen isotopic time series from Taiwan tree cellulose that span from 1190 AD to 2007 AD.