作者机构：
[Liu, Ji; Liu, Muxing; Zhang, Hailin; Yi, Jun] Key Lab Geog Proc Anal & Simulat, Wuhan 430079, Hubei, Peoples R China.;[Liu, Ji; Wang, Qiuyue; Liu, Muxing; Zhang, Hailin; Yi, Jun] Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan 430079, Peoples R China.;[Hu, Wei] New Zealand Inst Plant & Food Res Ltd, Private Bag 4704, Christchurch 8140, New Zealand.
通讯机构：
[Jun Yi] K;Key Laboratory for Geographical Process Analysis & Simulation, Hubei Province, Wuhan, 430079, China<&wdkj&>College of Urban and Environmental Sciences, Central China Normal University, Wuhan, 430079, China
关键词：
Volumetric soil water content;Wavelet analysis;Significant coherence area;Time scale;Vegetation type;Slope position
摘要：
Clarifying the mechanisms governing volumetric soil water content (VSWC) dynamics in soil profiles is essential, as it can help to elucidate soil water transport processes and improve the prediction accuracy of soil hydrological processes. Using Spearman's rank correlation and wavelet coherence analysis methods, similarity in soil profile VSWC dynamics and factors governing VSWC soil profile dynamics in upslopes and downslopes under three vegetation types (evergreen forest [EG], secondary deciduous forest mixed with shrubs [SDFS], and deforested pasture [DP]) at different time scales (hourly, daily, weekly, and monthly) and in different seasons were analyzed. The results revealed significant similarity in the VSWC of different soil depths (P < 0.01), with the similarity decreasing in accordance with the increment in soil depth. Greater VSWC similarity was found in EG than SDFS and DP sites and in upslope than downslope areas at both forest sites. The average significant coherence area (SCA) of VSWC similarity among surface and deep soil layers varied with the time scale, which was in the order of monthly (58.6%) > weekly (42.8%) > daily (21.8%). The effects of soil properties (e.g., texture, saturated hydraulic conductivity), rainfall, and potential evapotranspiration (ETp) on VSWC similarity were related to the time scale and season in which VSWC monitoring took place. Soil properties had apparent effects on VSWC similarity at longer time scales (i.e., monthly), with a high SCA. In contrast, the effects of rainfall and ETp on VSWC similarity were concentrated at weekly and daily scales, with a relatively low SCA. Rainfall and ETp dominated VSWC dynamics in the summer and fall, respectively. These results imply the use of measured VSWC at one soil depth to predict the VSWC at other soil depths was a reliable method. While the in-fluence of time scale effects and seasonal variations on prediction accuracy of VSWC should be considered. ](c) 2022 International Research and Training Center on Erosion and Sedimentation, China Water and Power Press, and China Institute of Water Resources and Hydropower Research. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY -NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
摘要：
Accurate geographic data of slums are important for handling urban poverty issues. Previous slum mapping studies using high-resolution or very-high-resolution (HR/VHR) remotely sensed (RS) images are commonly not suitable for city-wide scale tasks. This study aims to efficiently generate a slum map on a city-wide scale using freely accessed multispectral medium-resolution (MR) Sentinel-2 images. Composite slum spectral indices (CSSIs) were initially proposed based on the shapes of spectral profiles of slums and nonslums and directly represent slum characteristics. Specifically, CSSI-1 denotes the normalized difference between the shortwave infrared bands and the red edge band, while CSSI-2 denotes the normalized difference between the blue band and the green band. Furthermore, two methods were developed to test the effectiveness of CSSIs on slum mapping, i.e., the threshold-based method and the machine learning (ML)-based method. Experimental results show that the threshold-based method and the ML-based method achieve intersection over unions (IoU) of 43.89% and 54.45% in Mumbai, respectively. The accuracies of our methods are comparable to or even higher than the accuracies reported by existing methods using HR/VHR images and transfer learning. The threshold-based method exhibits a promising performance in mapping slums larger than 5 ha, while the ML-based method refines mapping accuracies for slum pockets smaller than 5 ha. The threshold-based method and the ML-based method produced the slum map in Mumbai in 2 and 28 min, respectively. Our methods are suitable for rapid large-area slum mapping owing to the high data availability of Sentinel-2 images and high computational efficiency.
期刊：
ISPRS Journal of Photogrammetry and Remote Sensing,2023年205:34-49 ISSN：0924-2716
通讯作者：
Hu, Q
作者机构：
[Xu, Baodong; Shi, Zhihua; Cai, Zhiwen] Huazhong Agr Univ, Coll Resources & Environm, Wuhan 430070, Peoples R China.;[Hu, Q; Hu, Qiong; Yang, Jingya] Cent China Normal Univ, Coll Urban & Environm Sci, Hubei Prov Key Lab Geog Proc Anal & Simulat, Wuhan 430079, Hubei, Peoples R China.;[Zhang, Xinyu; You, Liangzhi; Wei, Haodong] Huazhong Agr Univ, Macro Agr Res Inst, Coll Plant Sci & Technol, Wuhan 430070, Peoples R China.;[Li, Wenjuan; Yang, Jingya] Chinese Acad Agr Sci, Inst Agr Resources & Reg Planning, State Key Lab Efficient Utilizat Arid & Semi arid, Beijing 100081, Peoples R China.;[Zeng, Yelu] China Agr Univ, Coll Land Sci & Technol, Beijing 100083, Peoples R China.
通讯机构：
[Hu, Q ] C;Cent China Normal Univ, Coll Urban & Environm Sci, Hubei Prov Key Lab Geog Proc Anal & Simulat, Wuhan 430079, Hubei, Peoples R China.
关键词：
Agricultural field parcel delineation Deep learning Multimodal satellite data Spatiotemporal fusion Spatial transferability
摘要：
Accurate spatial information for agricultural field parcels is important for agricultural production management and understanding agro-industrialization and intensification. However, traditional remote sensing methods that rely on single-modal or single-date data struggle to identify heterogeneous field parcels, particularly in regions dominated by smallholder farming systems. To address this challenge, we proposed a Dual branch Spatiotemporal Fusion Network (DSTFNet) that integrated very high-resolution (VHR) images and medium-resolution satellite image time series (MRSITS) to extract agricultural field parcels over various landscapes. The DSTFNet consisted of two branches: a spatial branch that extracted spatial features from VHR images and a temporal branch that explored seasonal spectral dynamics from MRSITS data by using ConvLSTM units and an attention module. We evaluated the DSTFNet in four regions across China by using GF-2 and Sentinel-2 data. The results showed that DSTFNet performed well in delineating agricultural field parcels, achieving the highest Matthew's correlation coefficient (MCC) = 0.823 for the field extent, the highest F1-score of edge (Fedge) = 0.865 for field boundary, and the lowest errors of segmentation evaluation index (SEI) = 0.191 for the vectorized field parcels in Hubei province. In addition, DSTFNet significantly outperformed two single-branch models that used VHR or MRSITS alone, as well as existing BsiNet, ResUNet_a, UNet and RAUNet models. DSTFNet also showed good spatial transferability in distinct regions without training data (on average, MCC = 0.728, Fedge = 0.729, and SEI = 0.281 for three target regions). Using limited training data to fine-tune the DSTFNet can further improve its ability to delineate field parcels over complex regions. The visualization analysis of temporal attention weights demonstrated that DSTFNet can well capture cropland spectral dynamics, making it advantageous in extracting diverse cropland parcels. By exploiting important spectral, spatial and temporal information from multimodal satellite data, DSTFNet provided an effective, robust, and transferable solution for accurately delineating agricultural field parcels across heterogeneous farming systems.
期刊：
Pest Management Science,2023年79(7):2591-2602 ISSN：1526-498X
通讯作者：
Ran Meng<&wdkj&>Ran Meng Ran Meng Ran Meng
作者机构：
[Meng, Ran; Lv, Zhengang; Zhou, Longfei; Xu, Binyuan; Sun, Rui] Huazhong Agr Univ, Coll Resources & Environm, Wuhan, Peoples R China.;[Meng, Ran] HIT Inst Artificial Intelligence Co Ltd, Harbin, Peoples R China.;[Yang, Wanneng; Chen, Gengshen] Huazhong Agr Univ, Natl Ctr Plant Gene Res Wuhan, Natl Key Lab Crop Genet Improvement, Hubei Hongshan Lab, Wuhan, Peoples R China.;[Liang, Linlin] Chinese Acad Sci, Aerosp Informat Res Inst, Beijing, Peoples R China.;[Zhao, Feng] Cent China Normal Univ, Coll Urban & Environm Sci, Key Lab Geog Proc Anal & Simulat Hubei Prov, Wuhan, Peoples R China.
通讯机构：
[Ran Meng; Ran Meng Ran Meng Ran Meng] C;College of Resources and Environment, Huazhong Agricultural University, Wuhan, China<&wdkj&>HIT Institute for Artificial Intelligence Co. Ltd, Harbin, China
作者机构：
[Tao, Jianbin; Zhou, Yang; Zhang, Xinyue; Jiang, Qiyue; Zhou, Y] Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat Hubei Prov, Sch Urban & Environm Sci, Wuhan 430079, Peoples R China.;[Liu, Yiqing] Beijing Normal Univ, Inst Disaster Risk Sci, Fac Geog Sci, Beijing 100875, Peoples R China.
通讯机构：
[Zhou, Y ] C;Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat Hubei Prov, Sch Urban & Environm Sci, Wuhan 430079, Peoples R China.
关键词：
cropping intensity;temporal mixture analysis;endmember;unmixing;time series images
摘要：
Agricultural cropping intensity plays an important role in evaluating the food security and the sustainable development of agriculture. The existing indicators measuring cropping intensity include cropping frequency and multiple cropping index. As a nominal measurement, cropping frequency classifies crop patterns into single-cropping and/or double-cropping and leads to information loss. Multiple cropping index is calculated on the basis of statistical data, ignoring the spatial heterogeneity within the administrative region. Neither of these indicators can meet the requirements of precision agriculture, and new methods for fine cropping intensity mapping are still lacking. Time series remote sensing data provide vegetation phenology information and reveal temporal development of vegetation, which can be used to facilitate the fine cropping intensity mapping. In this study, a new temporal mixture analysis method is introduced to estimate the abundance level cropping intensity from time series remote sensing data. By analyzing phenological characteristics of major land-cover types in time series vegetatiosacan indices, a novel feature space was constructed by using the selected PCA components, and three unique endmembers (double-cropping, natural vegetations and water bodies) were found. Then, a linear spectral mixture analysis model was applied to decompose mixed pixels by replacing spectral data with multi-temporal data. The spatio-temporal continuous, fine resolution, abundance level cropping intensity maps were produced for the North China Plain and the middle and lower reaches of the Yangtze River Valley. The experiments indicate a good result at both county and pixel level validation. The method of manually delineating endmembers can well balance the accuracy and efficiency. We also found the size of the study area has little effect on the unmixing accuracy. The results demonstrated that the proposed method can model cropping intensity finely at large scale and long temporal span, at the same time with high efficiency and ease of implementation.
作者机构：
[Chen, Wei; Li, Siliang; Jiang, Bohan] Tianjin Univ, Inst Surface Earth Syst Sci, Sch Earth Syst Sci, Tianjin 300072, Peoples R China.;[Chen, Wei; Li, Siliang; Jiang, Bohan] Haihe Lab Sustainable Chem Transformat, Tianjin 300192, Peoples R China.;[Chen, Wei; Li, Siliang; Jiang, Bohan] Tianjin Bohai Rim Coastal Earth Crit Zone Natl Obs, Tianjin 300072, Peoples R China.;[Dai, Xiaoai] Chengdu Univ Technol, Coll Earth Sci, Chengdu 610059, Peoples R China.;[Xu, Min] Chinese Acad Sci, Aerosp Informat Res Inst, State Key Lab Remote Sensing Sci, Beijing 100101, Peoples R China.
通讯机构：
[Wei Chen] I;[Xiaoai Dai] C;College of Earth Sciences, Chengdu University of Technology, Chengdu 610059, China<&wdkj&>Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China<&wdkj&>Haihe Laboratory of Sustainable Chemical Transformation, Tianjin 300192, China<&wdkj&>Tianjin Bohai Rim Coastal Earth Critical Zone National Observation and Research Station, Tianjin 300072, China
作者：
Wu, Tieniu;Cheng, Antai;Lin, Henry;Zhang, Hailin;Jie, Yi
期刊：
地球科学学刊,2023年34(5):1556-1566 ISSN：1674-487X
通讯作者：
Wu, TN
作者机构：
[Cheng, Antai; Wu, Tieniu; Jie, Yi; Zhang, Hailin] Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat, Wuhan 430079, Hubei Province, Peoples R China.;[Lin, Henry; Wu, Tieniu] Penn State Univ, Dept Ecosyst Sci & Management, University Pk, PA 16802 USA.;[Cheng, Antai; Wu, Tieniu; Jie, Yi; Zhang, Hailin] Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan 430079, Peoples R China.
通讯机构：
[Wu, TN ] C;Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat, Wuhan 430079, Hubei Province, Peoples R China.;Penn State Univ, Dept Ecosyst Sci & Management, University Pk, PA 16802 USA.;Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan 430079, Peoples R China.
关键词：
MIS 9;climatic fluctuation;Paleosol;S3;Chinese Loess Plateau;environmental geology
摘要：
Marine Isotope Stages (MIS) 9 has been proposed as an analog for the present warm period. However, detailed studies of this geological time period are rare in loess-paleosol sequence. In the Chinese Loess Plateau (CLP), the corresponding stratum is the third paleosol layer (S3). Here, we report the terrestrial reconstruction of climatic fluctuations during MIS 9 by analyzing the paleo-climate indexes of S3 with high sampling density. Our results showed that: (1) During the period of MIS 9, the main climatic sub-cycle was 29 ka; (2) MIS 9 could be divided into five sections, MIS 9a, 9b, 9c, 9d, and 9e. Among them, MIS 9a, 9c, and 9e were warm stages, while MIS 9b and 9d were cool intervals; and 3) There were also three swift warm-wet events and one cool-dry event, which occurred around 332-331, 324-323, 311-310, and 331-329 ka BP, respectively. The overall trend of paleo-climate fluctuation correlated approximately with SPECMAP, LR04 stack and Iberian margin deep-sea cores. This study suggested that the paleosol records in the southern margin of the CLP have global significance and contain more detailed climatic signals than marine deposits.
摘要：
The fast development of urban built-up areas in China is causing many problems, such as pollution, congestion, etc. How to effectively evaluate the coordination between urban areas and environmental problems has been attracting many scholars worldwide. This paper intends to discover this "secretary" through investigating the built-up areas and their accompanied economic and environmental factors over almost 30 years (1992 to 2020) in Nanjing, China. DMSP/OLS nighttime lights images from 1992 to 2013 and the NPP/VIIRS nighttime lights images from 2012 to 2022 are used for extraction of built-up areas. A spatiotemporal evolution model is established to evaluate whether the built-up areas have developed in coordination and the relationship between urban built-up areas and various factors, including compactness, the fractal dimension, boundary and shape changes, exhaust emissions, and the production of general industrial solid waste, which was further investigated to ascertain whether there was coordination or not. The investigated results discovered that Nanjing's built-up areas had maintained continuous growth from 1992 to 2020, with the compactness of built-up areas gradually decreasing from 0.42 to 0.23 and the built-up differentiation dimension changing from 1.31 to 1.39, demonstrating that built-up areas had gradually moved from a loose pattern to a compact pattern and from irregular development to balanced development in all directions. The macro model of the coordination index change trend is 0.847 from 1995 to 2020, which indicates that the coordination between urban built-up areas of development and their environments has been improving; however, the reduction in urban green space, the increase in waste emissions, and the increased production of general industrial solid waste has raised questions regarding sustainable development.
作者机构：
[Tang, Hui; Ao, Rongjun; Zhou, Xiaoqi; Aihemaitijiang, Yierfanjiang; Chen, Jing] Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat Hubei Prov, Wuhan, Hubei, Peoples R China.;[Tang, Hui; Ao, Rongjun; Zhou, Xiaoqi; Aihemaitijiang, Yierfanjiang; Chen, Jing] Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan, Hubei, Peoples R China.;[Tang, Hui] Hunan City Univ, Sch Architecture & Urban Planning, Yiyang, Hunan, Peoples R China.
通讯机构：
[Aihemaitijiang, Y ] C;Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat Hubei Prov, Wuhan, Hubei, Peoples R China.;Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan, Hubei, Peoples R China.
摘要：
High-quality regional development should be promoted by facilitating inter-regional mobility of heterogeneous labor force to optimize its spatial allocation. This study incorporates skill relatedness into spatial categorization and selection effects, and explores how skill-relatedness affects the location choice of heterogeneous labor force. To do so, we use labor force migration data and employee data by occupation subcategory from the 2000 National Population Census and 2015 National Population Sample Survey. The empirical evidence provides three major findings. First, there are significant regional differences in labor migration rates by the occupational group between cities in China, and the trend is increasing. Regional concentration of location choice is increasing and six significant agglomerations are formed. Second, skill relatedness positively affects the location choice of the heterogeneous labor force in Chinese cities. When cities' skill-relatedness is more robust, influence on labor location choice is more remarkable. In cities with high-size classes, the effect of high-skill relatedness on labor location choice is higher. Third, labor force with solid skill relatedness with regional employment moves to the location owing to the spatial sorting effect. Labor force without skill relatedness or weak relatedness moves out or does not move to the location owing to the spatial selection effect.
关键词：
Gully erosion;Soil depth;Area of collapsing wall;Erosion rate
摘要：
Gully erosion, a spectacular erosional landform in the hilly areas of southern China, poses an enormous threat to local sustainable economic development and ecological security. The depth of granite weathering mantle in-creases from north to south, which is consistent with the increase of gully density and accelerated soil loss. However, the spatial distribution of soil depth in gully areas remains unclear. Herein, soil depth was measured by field sampling investigation, and soil depth mapping was established using the Fuzzy c-means algorithm. To explore the relationship between soil depth and gully erosion rate, gully characteristics and erosion process were monitored by unmanned aerial vehicle. The results showed that the gully density increased from Tongcheng (29 degrees 2 & PRIME;- 29 degrees 24 & PRIME; N) to Wuhua (23 degrees 23 & PRIME;- 24 degrees 12 & PRIME; N) in the range of 11.25-61.75 gullies/km2, in contrast to an opposite trend in the soil depth range from 180 to 5 cm. Additionally, soil depth mapping by fuzzy c-means algorithm performed well in gully areas, with overall accuracy, Pearson correlation coefficient, and agreement coefficient reaching 81.60%, 0.90, and 0.97, respectively. Moreover, the gully erosion rate in the range of 7.60-29.08 m3 yr.-1 had a significant positive linear relationship with the area of collapsing wall (R2 = 0.54, p < 0.05). Based on this relationship, a power function was established between soil depth and gully erosion rate (R2 = 0.41, p < 0.01), which provides a possibility for effective prediction of gully erosion. This study facilitates a better understanding of the gully erosion mechanism and its effective control.
通讯机构：
[Wang, Y ] 1;186 Hongqi Middle Rd, Zhifu Dist 410125, Yantai, Peoples R China.
关键词：
Soil ecological stoichiometry;Stream water ecological stoichiometry;Nitrogen and phosphorus loss;Soil nutrient limitation;Water nutrient limitation;Eutrophication
摘要：
Whether and how to synchronously regulate stream water nitrogen (N) and phosphorus (P) concentrations and ratios is a major challenge for sustainable aquatic functions. Soil carbon (C):N:P ratios influence soil N and P stocks and biogeochemical processes that elicit subsequent substantial impacts on stream water N and P con-centrations and ratios. Therefore, bridging soil and stream water with ecological stoichiometry is one of the most promising technologies for improving stream water quality. Here, we quantified the ecological stoichiometry of soil and stream water relationships across nine catchments. Soil C:P ratio was the main driver of water quality, showing negative correlations with stream water N and P concentrations, and positive correlations with the N:P ratio in P-limited catchments. We revealed that soil C:P ratios higher than 97.8 mol mol- 1 are required to achieve the simultaneous regulation of stream water N and P concentrations below the eutrophication threshold and make algal growth P-limited. Furthermore, we found that the relationships between catchment landscape and soil ecological stoichiometry likely provided practical options for regulating soil ecological stoichiometry. Our work highlights that soil ecological stoichiometry can effectively indicate the amount and proportion of soil N and P losses, and can be intervened through rational landscape planning to achieve sustainable aquatic eco-systems in catchments.
作者机构：
[Liu, Weihang; Sun, Ran; Li, Yan; Chen, Shuo; Li, Zitong; Ye, Tao; Liu, Yiqing] Beijing Normal Univ, State Key Lab Earth Surface Proc & Resource Ecol E, Beijing, Peoples R China.;[Liu, Weihang; Sun, Ran; Chen, Shuo; Li, Zitong; Ye, Tao; Liu, Yiqing] Beijing Normal Univ, Key Lab Environm Change & Nat Disasters, Minist Educ, Beijing, Peoples R China.;[Liu, Weihang; Sun, Ran; Chen, Shuo; Li, Zitong; Ye, Tao; Liu, Yiqing] Minist Educ, Minist Emergency Management, Acad Disaster Reduct & Emergency Management, Beijing, Peoples R China.;[Liu, Weihang; Sun, Ran; Chen, Shuo; Li, Zitong; Ye, Tao; Liu, Yiqing] Beijing Normal Univ, Fac Geog Sci, Beijing, Peoples R China.;[Li, Yan] Beijing Normal Univ, Inst Land Surface Syst & Sustainable Dev, Fac Geog Sci, Beijing, Peoples R China.
通讯机构：
[Ye, T ] B;Beijing Normal Univ, State Key Lab Earth Surface Proc & Resource Ecol E, Beijing, Peoples R China.;Beijing Normal Univ, Key Lab Environm Change & Nat Disasters, Minist Educ, Beijing, Peoples R China.;Minist Educ, Minist Emergency Management, Acad Disaster Reduct & Emergency Management, Beijing, Peoples R China.;Beijing Normal Univ, Fac Geog Sci, Beijing, Peoples R China.
摘要：
Understanding how crop phenology responds to climate change is critical for enabling agricultural adaptation measures. Pre-season temperature alone leads to well-understood changes in crop phenology. Nevertheless, the modulation effect of concurrent precipitation extremes on the response to temperature extremes has been largely under-addressed. Here, we investigate the response of rice transplanting dates to pre-season temperature extremes and reveal the modulation effects of concurrent precipitation extremes by using station-observed rice transplanting dates from 1981 to 2018 across mainland China. We also evaluate the performance of a remotely sensed phenology product, ChinaCropPhen1km, in reproducing the above temperature responses and modulation effects. Our results showed that transplanting dates tended to advance in response to an extremely hot pre-season, while concurrent extreme drought offset the advance by up to 2.6 days. Transplanting dates tended to be delayed in response to an extremely cold pre-season, while concurrent extreme precipitation exacerbated the delay by up to 1 day. Responses to temperature extremes and modulation effects were divergent across different regions. Under extremely hot conditions, transplanting dates advanced further in hotter and wetter regions, while under extremely cold pre-seasons, transplanting dates delayed less in colder and drier regions. Transplanting dates from the ChinaCropPhen1km product underestimated the responses to temperature extremes by up to 4.7 days and detected the opposite modulation effect compared to those obtained from observations. Our results highlight that the need to improve our understanding and modeling of modulation effects of precipitation extremes on temperature–phenology relationship, which benefits the field of agriculture risk analysis and climate change adaptation.
Concurrent extreme drought offset the extreme hot induced-advance, and extreme precipitation exacerbate the extreme cold induced-delay
Responses to temperature extremes and modulation effects of precipitation extremes are divergent across regions
Remotely sensed transplanting dates from ChinaCropPhen1km underestimate the responses to temperature extremes and modulation effects
Frequent climate extremes are projected with ongoing climate change. This paper reveals the effect of concurrent precipitation extremes in modulating rice transplanting date response to pre-season temperature extremes in China and assesses remotely sensed transplanting dates from the ChinaCropPhen1km product in reproducing the above temperature responses and modulation effects. Results show that concurrent precipitation extremes substantially influence the temperature–transplanting date relationship. Two kinds of modulation effects are detected: (a) concurrent extreme precipitation tends to exacerbate the extremely cold-induced delay by up to 1 day, and (b) concurrent extreme drought conditions tend to offset the extremely hot-induced advance by up to 2.6 days. From a spatial perspective, responses to temperature extremes and modulation effects are divergent across regions. Additionally, remotely sensed transplanting dates from the ChinaCropPhen1km product underestimate the temperature responses and detect the opposite modulation effects compared to observations. This study highlights the critical role of concurrent precipitation extremes in modulating temperature impact on crop phenology, which requires more understanding and modeling in future analysis.
摘要：
Nitrate-nitrogen (NO(3)(-)-N) loss is a significant contributor to water quality degradation in agricultural catchments. The amount of nitrogen (N) fertilizer input in citrus orchard is relatively large and results in significant NO(3)(-)-N loss, compared to cropland. To promote sustainable N fertilizer management, it is crucial to identify the sources of runoff NO(3)(-)-N loss in citrus orchards catchments. Particularly, we poorly know the sources of NO(3)(-)-N and the mitigation mechanisms in these areas, which are highly polluted with NO(3)(-)-N in water bodies. In this study conducted in central China, we conducted a field experiment with four treatments (CK: no N fertilizer; CF: conventional N fertilizer, 371.3kg N ha(-1) yr(-1) urea; OM: CF with organic manure; GM: CF with legume green manure) and a catchment-scale experiment in two citrus orchards (34.3%; 51.6%) catchments. To determine the source of runoff NO(3)(-)-N loss, we used the dual isotope tracer method (δ(15)N and δ(18)O of NO(3)(-)) to identify the sources of NO(3)(-)-N, and a 15-day incubation experiment to determine the potential and rate of soil N mineralization. Our findings revealed that soil organic nitrogen (SON) mineralization was the primary contributor to runoff NO(3)(-)-N loss, and soil N mineralization potential (0.65(⁎⁎⁎)) and rate (0.54(⁎⁎⁎)) were the key factors impacting NO(3)(-)-N loss. Interestingly, organic manure significantly increased 29.0% of NO(3)(-)-N loss derived from SON in the runoff by enhancing soil N mineralization potential (+36.6%) and rate (+77.1%). But green manure mulching significantly reduced the soil N mineralization rate (-18.6%) compared to organic manure application, making it the most effective measure to reduce NO(3)(-)-N loss (-12.4%). Our study highlights the critical role of regulating SON mineralization in controlling NO(3)(-)-N pollution in surface waters in citrus orchard catchments.
期刊：
Global Change Biology,2023年29(5):1377-1389 ISSN：1354-1013
通讯作者：
Yongshuo H. Fu<&wdkj&>Fanghua Hao<&wdkj&>Yongshuo H. Fu Yongshuo H. Fu Yongshuo H. Fu<&wdkj&>Fanghua Hao Fanghua Hao Fanghua Hao
作者机构：
[Zhang, Xuan; Chen, Shouzhi; Zhang, Jing; Wu, Zhaofei; Geng, Xiaojun; Fu, Yongshuo H.] Beijing Normal Univ, Coll Water Sci, Beijing 100875, Peoples R China.;[Geng, Xiaojun] Minist Water Resources, Gen Inst Water Resources & Hydropower Planning &, Beijing, Peoples R China.;[Hao, Fanghua; Wu, Hao] Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan 430079, Peoples R China.;[Tang, Jing] Lund Univ, Dept Phys Geog & Ecosyst Sci, Lund, Sweden.;[Tang, Jing] Univ Copenhagen, Dept Biol, Terr Ecol Sect, Copenhagen, Denmark.
通讯机构：
[Yongshuo H. Fu; Fanghua Hao; Yongshuo H. Fu Yongshuo H. Fu Yongshuo H. Fu; Fanghua Hao Fanghua Hao Fanghua Hao] C;College of Water Sciences, Beijing Normal University, Beijing, China<&wdkj&>College of Urban and Environmental Sciences, Central China Normal University, Wuhan, China
关键词：
autumnal foliar senescence;climatic warming;green season;spring leaf-out;thermal season
摘要：
Global warming leads to substantial changes in the thermal conditions for vegetative growth. Based on in situ and remote sensing‐based phenological observations, we show that global warming is extending both the thermal (potential) and green (actual) season of temperate deciduous trees, but green season extensions lag behind the thermal season by 7.9–11.1 days and this mismatch was mainly driven by tree's leaf‐out dates did not follow proportionately the strong advance in the thermal season onset. Our results call for caution when using thermal sums to predict future changes in plant vegetative growth or any processes involving plant development. Abstract Over the past decades, global warming has led to a lengthening of the time window during which temperatures remain favorable for carbon assimilation and tree growth, resulting in a lengthening of the green season. The extent to which forest green seasons have tracked the lengthening of this favorable period under climate warming, however, has not been quantified to date. Here, we used remote sensing data and long‐term ground observations of leaf‐out and coloration for six dominant species of European trees at 1773 sites, for a total of 6060 species–site combinations, during 1980–2016 and found that actual green season extensions (GS: 3.1 ± 0.1 day decade−1) lag four times behind extensions of the potential thermal season (TS: 12.6 ± 0.1 day decade−1). Similar but less pronounced differences were obtained using satellite‐derived vegetation phenology observations, that is, a lengthening of 4.4 ± 0.13 and 7.5 ± 0.13 day decade−1 for GS and TS, respectively. This difference was mainly driven by the larger advance in the onset of the thermal season compared to the actual advance of leaf‐out dates (spring mismatch: 7.2 ± 0.1 day decade−1), but to a less extent caused by a phenological mismatch between GS and TS in autumn (2.4 ± 0.1 day decade−1). Our results showed that forest trees do not linearly track the new thermal window extension, indicating more complex interactions between winter and spring temperatures and photoperiod and a justification of demonstrating that using more sophisticated models that include the influence of chilling and photoperiod is needed to accurately predict spring phenological changes under warmer climate. They urge caution if such mechanisms are omitted to predict, for example, how vegetative health and growth, species distribution and crop yields will change in the future.
作者机构：
[Zhang, Juan; Chen, Dong; Liu, Zhaojun; Xiong, Kangning; Gu, Xinyan; Zhang, Ning] Guizhou Normal Univ, Sch Karst Sci, Guizhou Engn Lab Karst Desertificat Control & Ecoi, Guiyang 550001, Peoples R China.;[Zhang, Juan; He, Lixiang] Guizhou Univ Finance & Econ, Sch Management Sci & Engn, Guiyang 550025, Peoples R China.;[He, Lixiang] Cent China Normal Univ, Sch Urban & Environm Sci, Wuhan 430079, Peoples R China.
通讯机构：
[Xiong, KN ] G;Guizhou Normal Univ, Sch Karst Sci, Guizhou Engn Lab Karst Desertificat Control & Ecoi, Guiyang 550001, Peoples R China.
关键词：
Natural World Heritage;Buffer zone;Conservation;Tourism;Coupling coordination;Libo-Huanjiang Karst
摘要：
Karst World Heritage Site (KWHS) combines high-grade landscape resources and a fragile ecological environment. As an essential tool for heritage conservation and maintaining local interests, its buffer zone is primarily located in remote villages, a crucial and challenging area for rural revitalization. The conflict between heritage conservation and development is particularly acute at the site. How to deal with the relationship between the heritage site's OUV conservation and the buffer zone's tourism industry development and realize the synergy between the two subsystems? Few studies have focused on it. There is an urgent need to explore the synergistic mechanism of the KWHS's OUV conservation and the buffer zone's tourism industry development. Accordingly, this study takes the Libo-Huanjiang KWHS, one of the 'South China Karst' series of heritage sites, as a case study. The coupling coordination degree model, gray correlation analysis (GCA), and Geographic Information System (GIS) spatial analysis are used. The results show that: (1) There is a synergistic effect between the Libo-Huanjiang KWHS's OUV conservation and its buffer zone's tourism industry development, showing a favorable trend. The mean value of the coupling coordination degree increased from 0.57 in 2015 to 0.63 in 2020, and the overall situation improved from barely coupling coordination state to primary coupling coordination. (2) Influenced by the main driving factors, such as NDVI, landscape dominance, government support for tourism development, tourists' satisfaction, and residents' support, the coupling coordination of the four tourist scenic areas in the study area differed slightly in 2015 and 2020. Yaoshan Ancient Village Scenic Area is the highest in both years, increasing from 0.69 to 0.81, followed by the Mengliu Buyi Scenic Area (0.59), Wanmu Meiyuan Scenic Area is relatively stable with a slight increase, and Lianshanwan Scenic Area (0.45) is the lowest. (3) The four dimensions of ecological resources, policy drivers, economy drivers, and social facilitators work together to create a synergistic mechanism between the KWHS's OUV conservation and the buffer zone's tourism industry development. Future research can promote synergy between the two by formulating a comprehensive plan, encouraging sustainable tourism, establishing a diversified tourism industry, strengthening heritage education and training, enhancing community participation, and reinforcing stakeholder cooperation.
作者机构：
[You, Liangzhi; Hu, Jie; Wei, Haodong; Chen, Yunping] Huazhong Agr Univ, Macro Agr Res Inst, Coll Plant Sci & Technol, Wuhan 430070, Peoples R China.;[Xu, Baodong; Zhang, Xinyu; Zhou, Wei; Cai, Zhiwen] Huazhong Agr Univ, Coll Resources & Environm, Wuhan 430070, Peoples R China.;[Wang, Cong] Cent China Normal Univ, Coll Urban & Environm Sci, Key Lab Geog Proc Anal & Simulat Hubei Prov, Wuhan 430079, Peoples R China.;[You, Liangzhi] Int Food Policy Res Inst, 1201 1 St NW, Washington, DC 20005 USA.;[Xu, Baodong] Beijing Normal Univ & Chinese Acad Sci, Aerosp Informat Res Inst, State Key Lab Remote Sensing Sci, Beijing 100101, Peoples R China.
通讯机构：
[Baodong Xu] C;College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China<&wdkj&>State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Aerospace Information Research Institute, Chinese Academy of Sciences and Beijing Normal University, Beijing 100101, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Paddy rice cropping patterns (PRCPs) play important roles in both agroecosystem modeling and food security. Although paddy rice maps have been generated over several regions using satellite observations, few studies have focused on mapping diverse smallholder PRCPs, which include crop rotation and are dominant cropping structures in South China. Here, an approach called the feature selection and hierarchical classification (FSHC) method was proposed to effectively identify paddy rice and its rotation types. Considering the cloudy and rainy weather in South China, a harmonized Landsat and Sentinel-2 (HLS) surface reflectance product was employed to increase high-quality observations. The FSHC method consists of three processes: cropping intensity mapping, feature selection, and decision tree (DT) model development. The FSHC performance was carefully evaluated using crop field samples obtained in 2018 and 2019. Results suggested that the derived cropping intensity map based on the Savitzky-Golay (S-G) filtered normalized difference vegetation index (NDVI) time series was reliable, with an overall accuracy greater than 93%. Additionally, the optimal spectral (i.e., normalized difference water index (NDWI) and land surface water index (LSWI)) and temporal (start-of-season (SOS) date) features for distinguishing different PRCPs were successfully identified, and these features are highly related to the critical growth stage of paddy rice. The developed DT model with three hierarchical levels based on optimal features performed satisfactorily, and the identification accuracy of each PRCP can be achieved approximately 85%. Furthermore, the FSHC method exhibited similar performances when mapping PRCPs in adjacent years. These results demonstrate that the proposed FSHC approach with HLS data can accurately extract diverse PRCPs over fragmented croplands; thus, this approach represents a promising opportunity for generating refined crop type maps.
作者：
Zheng, Jiangpeng;Huang, Zhou;Zhou, Xiao;Scheuer, Bronte;Wang, Han
期刊：
Sustainable Cities and Society,2023年99:104976 ISSN：2210-6707
通讯作者：
Huang, Z
作者机构：
[Huang, Zhou; Zheng, Jiangpeng; Huang, Z; Scheuer, Bronte] Peking Univ, Inst Remote Sensing & Geog Informat Syst, Sch Earth & Space Sci, Beijing 100871, Peoples R China.;[Huang, Zhou; Zheng, Jiangpeng; Scheuer, Bronte] Peking Univ, Beijing Key Lab Spatial Informat Integrat & Its Ap, Beijing 100871, Peoples R China.;[Zhou, Xiao] Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan 430079, Peoples R China.;[Wang, Han] Univ Hong Kong, Fac Architecture, Div Landscape Architecture, Future Urban & Sustainable Environm FUSE Lab, Hong Kong, Peoples R China.
通讯机构：
[Huang, Z ] P;Peking Univ, Inst Remote Sensing & Geog Informat Syst, Sch Earth & Space Sci, Beijing 100871, Peoples R China.
关键词：
CO2 emissions;Bus smart card;Spatiotemporal characteristics;Per person-kilometer;Emission reduction potential
摘要：
Human activities, primarily carbon dioxide emissions, have undeniably caused global warming. The transportation sector contributes about a quarter of global CO2 emissions. While replacing traditional buses with electric ones has reduced emissions, it is crucial to consider the indirect emissions resulting from electricity consumption. This study proposes a framework for modeling bus emissions using smart card data, integrating spatiotemporal distribution characteristics and emission reduction potentials. Our analysis reveals that routes spanning 10-30 km contribute to 81% of total bus emissions, with an average emission rate of 56.2 gCO2/per-km for residents traveling by bus. Bus emissions also exhibit cyclical variations during holidays, weekdays, and weekends, indicating spatial clustering and trends. Although the area within Beijing's 4th Ring Road constitutes only 13% of the total area within the 6th Ring Road, it generates almost half of the CO2 emissions. With urban expansion, total bus emissions increase gradually, but emission intensity decreases. This study emphasizes the potential for reducing emissions through improved public transportation operations. It recommends fully electrifying the bus fleet and employing low grid emission factors, which could reduce emissions by up to 71% compared to diesel options. Electrification of buses and optimizing power generation on the grid are essential priorities for emission reduction.
