Abstract. As the most severe ecological issue in southwest China, karst rocky desertification (KRD) has both threatened and constrained regional sustainable development. Comprehensively understanding the relationship between the evolution of KRD and relevant driving data would provide more information to combat KRD in such complex karst environments. Past studies have been limited in quantifying the relative importance of driving factors influencing fine-scale KRD evolution, and have also lacked insight into their interactive impacts. To address these issues, we have used geographical information system techniques and a geographical detector model to explore the spatial consistency of driving factors and their interactions in relation to the evolution of KRD. Changshun County in China was selected as a representative area for the study. Nine relevant driving factors, including both natural and anthropogenic factors, were studied in regard to their relationships with KRD transformation between 2000 and 2010. Our results demonstrate the relative importance of driving data in influencing the improvement and deterioration of KRD. Lithology, soil type and road influence are identified as the leading factors. Interestingly, to our study at least, there is no significant difference between the impacts of natural and anthropogenic factors influencing KRD improvement, and even natural factors have a higher impact on KRD deterioration. Factors were found to enhance the influence of each other for KRD transformation. In particular, the results show a non-linearly enhanced effect between driving factors, which significantly aggravates KRD. New information found in our study helps to effectively control and restore areas afflicted by KRD.

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Abstract. We examine the spatial and temporal relationship between chromospheric H β flares and photospheric current helicities in active regions. All of the data were obtained by the vector magnetograph system at Huairou Solar Observing Station of Beijing Astronomical Observatory. We focus our analysis on NOAA Active Region 6233, which was observed on 30 August 1990. The result shows that rapid and substantial changes of distribution of current helicity in an area or in its vicinity are most likely to trigger flares, but no compelling correlation between peaks of current helicity and flare sites. Furthermore, we study the influence of flares on helicity for several other active regions. We find that the time variations of current helicity in the active regions with highly productive flares are more significant than those of the poorly flare-productive active regions, and that the magnitude of current helicity does not always decrease after flares. Therefore we conclude that the rate of variation of current helicity may be considered as an indicator of flare activity.In this paper we describe the specification of the instrumentation and data used, and we describe the methods for computing helicity. The noises and errors in our data are estimated to be at the 2 − 3σ level.