Lake Urmia, the second largest saline Lake on earth and a highly endangered ecosystem, is on the brink of a serious environmental disaster similar to the catastrophic death of the Aral Sea. Progressive drying has been observed during the last decade, causing dramatic changes to Lake Urmia's surface and its regional water supplies. The present study aims to improve monitoring of spatiotemporal changes of Lake Urmia in the period 1975-2015 using the multi-temporal satellite altimetry and Landsat (5-TM, 7-ETM+ and 8-OLI) images. In order to demonstrate the impacts of climate change and human pressure on the variations in surface extent and water level, Lake Sevan and Van Lake with different characteristics were studied along with the Urmia Lake. Normalized Difference Water Index-Principal Components Index (NDWI-PCs), Normalized Difference Water Index (NDWI), Modified NDWI (MNDWI), Normalized Difference Moisture Index (NDMI), Water Ratio Index (WRI), Normalized Difference Vegetation Index (NDVI), Automated Water Extraction Index (AWEI), and MultiLayer Perceptron Neural Networks (MLP NNs) classifier were investigated for the extraction of surface water from Landsat data. The presented results revealed that MLP NNs has a better performance in the cases where the other models generate poor accuracy. The results show that the area of Lake Sevan and Van Lake have increased while the area of Lake Urmia has decreased by~65.23% in the past decades, far more than previously reported (~25% to 50%). Urmia Lake's shoreline has been receding severely between 2010 and 2015 with no sign of recovery, which has been partly blamed on prolonged droughts, aggressive regional water resources development plans, intensive agricultural activities, and anthropogenic changes to the system. The results also indicated that (among the proposed factors) changes in inflows due to overuse of surface water resources and constructing dams (mostly during 1995-2005) are the main reasons for Urmia Lake's shoreline receding. The model presented in this manuscript can be used by managers as a decision support system to find the effects of building new dams or other infrastructures.

“The Anthropocene” currently serves as a framework to acknowledge global human influences on the earth systems. Different prominent authors call for geographers and especially physical geographers to intensify their involvement in the discussions on the theme. A bibliometric analysis shows that geographers are already one of the leading contributors to the keyword Anthropocene in journal articles. While we generally support the standpoint of increased engagement with the topic, we want to emphasize that we need to do more than only attaching the “Anthropocene” label to our daily research practice. A critical engagement with and reflection of the research questions and contexts is needed to play a vital role as discussant in the debate. We should take advantage of the diverse themes, topics and viewpoints of our subject by actively following a more critical approach to our research practices in order to find those geographic ties that join us and our discipline and that enable us to contribute more substantially to the Anthropocene debate.

Recent studies have revealed that the influence of diurnal temperature on spring phenology is asymmetric, and the faster night-time warming in the Northern Hemisphere (NH) has a complex impact on spring phenology. Our understanding from the sensitivity of the start of the growing season (SOS) to daytime (S T _daytime) and night-time temperatures (S T _night-time) has urgently needs to be improved. In this study, the SOS sensitivity to diurnal temperature in the middle and high latitudes of the NH (>30 N) from 1982 to 2015 is estimated. The results indicate that although SOS showed stronger sensitivity to daytime than night-time temperature in most parts of the study areas, the influence of daytime temperature on SOS is decreasing, while the influence of night-time temperature on SOS is increasing. The variations in S T _daytime and S T _night-time along the latitude gradient were significantly correlated with the warming rate of the preseason diurnal temperature (p < .01). The SOS between 40 N and 70 N was more sensitive to daytime temperature, while S T _night-time was higher than S T _daytime at other latitudes due to topography and rapid night-time warming. On the altitude gradient, the SOS was more sensitive to daytime temperature in areas below 800 and 2,000-4,000 m. S T _night-time exceeded S T _daytime at other altitudes owing to nighttime warming relief of the severe restrictions on phenological processes and the reduction in frost risk. To reach a comprehensive characterization of the interaction between vegetation and climate systems, the current study suggests more investigation on the response of SOS to diurnal temperature on large scales.

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