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Icebergs are big chunks of ice floating on the ocean surface, and melting of icebergs contributes for the major part of freshwater flux into ocean. Dynamic monitoring of the icebergs in Antarctica and accurate estimation of their volume are important for predicting the trend of freshwater budget of the Southern Ocean. The iceberg freeboard is a key parameter for measuring the thickness and volume of an iceberg and is defined as the difference between the elevation of iceberg surface and sea level. So far, freeboards of icebergs have been successfully extracted using InSAR DEM, and the laser and radar altimeter. However, uncertainties exist in these results mainly caused by missed detection of small icebergs due to the spatially sparse and temporally incomplete data coverage. In addition to the above techniques, optical images can also be used to extract the iceberg freeboard based on its geometric relationship with shadow length, which can effectively compensate for the above shortcomings. Although the feasibility has been preliminarily presented, the precision and extensive application of shadow-height method deserves further research, such as estimating the basal melting of icebergs. In this work, we tested an optical image-based freeboard extraction method over icebergs in Prydz Bay, Antarctica. A normalized shadow pixel index (NSPI) is designed to identify iceberg shadows with different shapes in HY-1C/D CZI and Sentinel-2 MSI optical images. The iceberg freeboard can be determined with an acceptable precision (2 m) in optical images compared with laser altimeter (i.e. ICESat-2) measurements. Moreover, basal melting of icebergs has been assessed according to the variation of freeboard using repeated optical observations. The results indicate that icebergs in the study area were with a mean freeboard of about 56 m in early December 2022, and experienced a decrease in freeboard of 1.9 m within two months, in correspondence with the Antarctic seasonal trend. The methodological framework, therefore, turns out to be a reliable complementary approach to studying the iceberg freeboard in polar regions. [ABSTRACT FROM AUTHOR]

This study aims to support sustainable urban and environmental planning by using urban growth simulation models, in which environmental quality is employed as one of the inputs. We proposed an extended SLEUTH urban growth model (UGM) for the regions threatened by environmental quality degradation caused by uncontrolled urban expansion. In this model, habitat quality is assessed by the InVEST model and is used to represent environmental quality, which is utilized in urban growth simulation. The habitat quality map is used to replace the slope layer as input for the SLEUTH model's urban growth simulation for cities where relatively flat topography makes this layer of minimal explanatory value. The extended SLEUTH UGM was calibrated using data for Changzhou city, China in 1990, 2000, 2010, and 2014. The best value of the Optimal SLEUTH Metric (OSM) was calculated for both the standard SLEUTH UGM and the extended SLEUTH UGM independently. The OSM value for the latter model was much higher than that of the former model, which indicated that the extended model provided a better explanation of urban growth in the study area. The calibrated extended SLEUTH UGM was applied to predict growth in Changzhou city from 2014 to 2030. The result showed that the urban area is expected to expand about 626 km2 by 2030. Comparison with the prediction result by using standard SLEUTH UGM showed that the area with high habitat quality could be reserved and the urban expansion could be limited by using our model. The findings demonstrate that the extended SLEUTH UGM could be a valuable tool for sustainable urban and environmental planning and management in developing regions where environmental protection should be considered as one of the major land-use objectives in their rapid urbanization process.

Comprehensive land consolidation (CLC) is a strategy to promote the intensive, efficient, and sustainable use of land, and is of great significance in repairing degraded land in oases, reversing the decline of the countryside, and activating multiple values of land use. However, how to scientifically assess and zoning management of CLC in dryland oases remains an open question. In this study, a comprehensive analytical framework was established to assess the characteristics of land‐use transformation and the potential for CLC using remotely sensed and geospatial data and spatial analysis methods, a multi‐objective territorial differentiation model, and collaborative path for CLC in oasis villages was proposed. The following key results were obtained. (1) From 2009 to 2018, urban and rural settlements in the hinterland of the Weiku Oasis expanded by 40 km2, and shrub forests and grasslands in the oasis‐desert transition zone shrank substantially by 21.13 km2. The newly cultivated farmland in the oasis‐desert transition zone only offset 62.9% of the occupied farmland in the hinterland of the oasis. (2) The pattern of comprehensive rural land consolidation potential in the Weiku Oasis was consistent with territorial differentiation, with a gradient decrease from the hinterland of the oasis to the desert. The average potential for Comprehensive land consolidation (PCLC) index was 0.31. (3) Three consolidation priorities and six consolidation types were identified for the proposal of 14 combined modes of CLC. Territorial differentiation with respect to the combined modes was discussed. Overall, this study provides useful insights for promoting efficient and sustainable utilization of oasis land resources and implementing zoning management. [ABSTRACT FROM AUTHOR]