Mining transition rules of cellular automata for simulating urban expansion by using the deep learning techniques

Along with the gradually accelerated urbanization process, simulating and predicting the future pattern of the city is of great importance to the prediction and prevention of some environmental, economic and urban issues. Previous studies have generally integrated traditional machine learning with cellular automaton (CA) models to simulate urban development. Nevertheless, difficulties still exist in the process of obtaining more accurate results with CA models; such difficulties are mainly due to the insufficient consideration of neighborhood effects during urban transition rule mining. In this paper, we used an effective deep learning method, named convolution neural network for united mining (UMCNN), to solve the problem. UMCNN has substantial potential to get neighborhood information from its receptive field. Thus, a novel CA model coupled with UMCNN and Markov chain was designed to improve the performance of simulating urban expansion processes. Choosing the Pearl River Delta of China as the study area, we excavate the driving factors and the transformational relations revealed by the urban land-use patterns in 2000, 2005 and 2010 and further simulate the urban expansion status in 2020 and 2030. Additionally, three traditional machine-learning-based CA models (LR, ANN and RFA) are built to attest the practicality of the proposed model. In the comparison, the proposed method reaches the highest simulation accuracy and landscape index similarity. The predicted urban expansion results reveal that the economy will continue to be the primary factor in the study area from 2010 to 2030. The proposed model can serve as guidance in urban planning and government decision-making.     

Overflow probability of the Salt Lake in Hoh Xil Region

After the bursting of Huiten Nor in Hoh Xil Region in September, 2011, the topic on whether the water overflowed from the Salt Lake would enter into the Chumaer River and become the northernmost source of the Yangtze River has aroused wide concern from public and academic field. Based on Landsat TM/ETM+/OLI remote sensing images during 2010–2015, SRTM 1 arc-second data, Google Earth elevation data and the observation data from the Wudaoliang meteorological station, the study initially analyzed the variations of the Salt Lake and its overflowing condition and probability. The results showed that the area of the Salt Lake expanded sharply from October 2011 to April 2013, and then it stepped into a stable expansion period. On October 27, 2015, the area of the Salt Lake had arrived at 151.38 km², which was about 3.35 times the area of the lake on March 3, 2010. The Salt Lake will overflow when its area reaches the range from 218.90 km² to 220.63 km². Due to the differences between SRTM DEM and Google Earth elevation data, the water level of the Salt Lake simulated would be 12 m or 9.6 m higher than the current level when the lake overflowed, and its reservoir capacity would increase by 23.71 km³ or 17.27 km³, respectively. Meanwhile, the overflowed water of the Salt Lake would run into the Qingshui River basin from its eastern part. Although the Salt Lake does not overflow in the coming decade, with watershed expansion of the Salt Lake and the projected precipitation increase in Hoh Xil region, the probability of water overflow from the Salt Lake and becoming a tributary of the Yangtze River will exist in the long term.     

Temporal and spatial variations of bacterial community compositions in two estuaries of Chaohu Lake

The distinctive estuary hydrodynamics and nutrient input make the estuary ecosystem play a key role in lake ecosystems. The Nanfei River and Zhaohe River are two main inlets of Chaohu Lake, Anhui, East China. We selected estuaries of the two rivers as representative areas to study temporal and spatial changes of bacterial communities. In August (summer) and November (autumn) 2016 and February (winter) and May (spring) 2017, 16 water and sediment samples were collected from the estuaries. Physicochemical characteristics indicate significant differences in the nutritional status and eutrophication index of the estuaries due mainly to organic input. Examination of the number of operational taxonomic units, the diversity index, the community composition, and redundancy analysis revealed the following. First, the existence of varying degrees of seasonal differences in the distribution of almost all bacteria. In addition, the species diversity in the sediment samples was higher than that in the water samples, and the dominant species differed also among these samples. Second, a large number of unknown genera were detected, especially in the sediment samples, such as unclassified Xanthomonadales incertae sedis, unclassified Anaerolineaceae, and unclassified Alcaligenaceae. Last, TP, TN, and TOC were the main influential factors that affected the bacterial community structure.     

瞬变电磁法在煤矿水患区预测中的应用

在青杠林煤矿工作中,利用MSD-1脉冲瞬变电磁仪,选用100m×100m正方形重叠回线装置,观测时窗8～25920μs,采样道数40道进行数据采集。经数据处理,获得该区多测道剖面图及虚拟全区视由阻率剖面图,从中解释其含水岩溶管道3处,含水岩溶空洞2处,节理、裂隙5条。根据依照水患危险程度划分标准该区岩溶管道、空洞的位置及节理、裂隙的贯穿深度,将该区定为中等程度隐患预测区。     

Geological characteristics and evolution of the eastern Qinghai-Tibetan plateau since the late Cenozoic

The eastern edge of the Qinghai-Tibetan plateau developed an integrated series of late Cenozoic lacustrine, loess, red and moraines deposits. Various genetic sediments recorded rich information of Quaternary palaeoenvironment changes. Xigeda Pliocene lacustrine deposits, formed during 4.2 Ma B.P.–2.6 Ma B.P., experienced nine periodic warm-cold stages. Eolian deposition in western Sichuan began at 1.15 Ma B.P., and the loess-soil sequences successively record fourteen palaeomonsoon change cycles. Red clay in the Chengdu plain record five stages of paleoclimatic change stages since 1.13 Ma B.P.. There was an old glacial period of 4.3 Ma B.P. in the eastern Qinghai-Tibetan plateau. During the Quaternary, there were five extreme paleoclimatic events corresponding to five glaciations. __________ Translated from Geological Bulletin of China, 2007, 26(12): 1620–1626 [译自: 地质通报]     

冀中坳陷武清凹陷苏50井石炭-二叠纪煤系的成烃演化

基于对武清凹陷苏50井的石炭-二叠纪煤系的构造—埋藏史研究,结合磷灰石裂变径迹测试及矿物包裹体分析,运用EASY%Ro数值模拟技术,研究了苏50井石炭-二叠系烃源岩的生烃演化历史,揭示了苏50井处石炭-二叠系烃源岩曾发生过3次重要的生烃作用过程,分别发生在海西-印支期、燕山期与喜马拉雅晚期,主要生烃作用发生在喜马拉雅晚期,并指出武清凹陷是华北石炭-二叠系煤成气勘探的有利地区之一。     

Estimation of Rice Yield with a Process-Based Model and Remote Sensing Data in the Middle and Lower Reaches of Yangtze River of China

Accurate simulation of rice yield is very important and vital for agriculture and food security. This study has analyzed the applicability of the RS-P-YEC (the remote-sensing-photosynthesis-yield estimation for crops) model for the rice yield simulation of the Middle and Lower Reaches of Yangtze River (MLRYR) in China. The simulated rice yield was compared with the actual statistical dataset, so as to obtain the accuracy of the model results. The results showed that the correlation coefficients (R) between simulated rice yield and statistical data is 0.708 (P < 0.01), the average relative errors were 9, 6.5, 7.2 %, and the root mean square errors were 777.5, 606.4, 693.4 kg/ha in 2007, 2008 and 2009, respectively. It indicated that the RS-P-YEC model can be used to estimate rice yield in the MLRYR region of China.     

无人机与国产高分技术在“6·24”茂县滑坡灾情应急监测中的应用

本文运用无人机与国产高分技术获取了“6·24”茂县特大滑坡灾区数据源,分析了本次滑坡成因,利用无人机航摄数据与国产高分遥感数据开展了灾区受灾前后灾情对比,结合本次滑坡事故形成过程及受灾情况等信息,初步判识出灾区周边有4处疑似地灾隐患点.结果表明,无人机与国产高分技术相结合,可实现灾区应急地形生成与形变监测,对地灾潜在隐患的早期识别、发现及滑坡灾后灾情应急监测具有一定的指导意义.     

Spatiotemporal variability of four precipitation-based drought indices in Xinjiang,China

Global increases in duration and prevalence of droughts require detailed drought characterization at various spatial and temporal scales. In this study, drought severity in Xinjiang, China was investigated between 1961 and 2012. Using meteorological data from 55 weather stations, the UNEP (1993) index (I _A), Erinç’s aridity index (I _m), and Sahin’s aridity index (I _sh) were calculated at the monthly and annual timescales and compared to the Penman-Monteith based standard precipitation evapotranspiration index (SPEI_PM). Drought spatiotemporal variability was analyzed for north (NX), south (SX), and entire Xinjiang (EX). I _m could not be calculated at 51 stations in winter as T _max was below 0. At the monthly timescale, I _A, I _m, and I _sh correlated poorly to SPEI_PM because of seasonality and temporal variability, but annual I _A, I _m, and I _sh correlated well with SPEI_PM. Annual I _A, I _m, and I _sh showed strong spatial variability. The 15 extreme droughts denoted by monthly SPEI_PM occurred in NX but out of phase in SX. Annual precipitation, maximum temperature, and relative and specific humidity increased, while air pressure and potential evapotranspiration decreased over 1961–2012. The resulting increases in the four drought indices indicated that drought severity in Xinjiang decreased, because the local climate became warmer and wetter.

     

Simulating urban land-use changes at a large scale by integrating dynamic land parcel subdivision and vector-based cellular automata

Cellular automata (CA) have been widely used to simulate complex urban development processes. Previous studies indicated that vector-based cellular automata (VCA) could be applied to simulate urban land-use changes at a realistic land parcel level. Because of the complexity of VCA, these studies were conducted at small scales or did not adequately consider the highly fragmented processes of urban development. This study aims to build an effective framework called dynamic land parcel subdivision (DLPS)-VCA to accurately simulate urban land-use change processes at the land parcel level. We introduce this model in urban land-use change simulations to reasonably divide land parcels and introduce a random forest algorithm (RFA) model to explore the transition rules of urban land-use changes. Finally, we simulate the land-use changes in Shenzhen between 2009 and 2014 via the proposed DLPS-VCA model. Compared to the advanced Patch-CA and RFA-VCA models, the DLPS-VCA model achieves the highest simulation accuracy (Figure-of-Merit = 0.232), which is 32.57% and 18.97% higher respectively, and is most similar to the actual land-use scenario (similarity = 94.73%) at the pattern level. These results indicate that the DLPS-VCA model can both accurately split the land during urban land-use changes and significantly simulate urban expansion and urban land-use changes at a fine scale. Furthermore, the land-use change rules that are based on DPLS-VCA mining and the simulation results of several future urban development scenarios can act as guides for future urban planning policy formulation.