Based on the in situ optical measurements in the Bohai Sea of China, which belongs to a typical case-2 water area, we studied the characteristics of DCM (deep chlorophyll maximum) such as its spatial distribution, ver...Based on the in situ optical measurements in the Bohai Sea of China, which belongs to a typical case-2 water area, we studied the characteristics of DCM (deep chlorophyll maximum) such as its spatial distribution, vertical profile, etc. We found that when the depth of the chlorophyll maximum is comparatively small, even in turbid coastal water regions, there is always a good correlation between the concentrations of chlorophyll maximum and the satellite-received signals in blue-green spectral bands; the correlation is even better than that between the surface chlorophyll concentrations and the satellite-received signals. The strong correlation existing even in turbid coastal water regions indicates that an ocean color model to retrieve the concentration of DCM can be constructed for coastal waters if a comprehensive knowledge of the vertical distribution of chlorophyll concentration in the Bohai Sea of China is available.展开更多
Petermann Glacier is a marine-terminating outlet glacier that had a 70 km-long floating ice tongue prior to a ～ 270 km2 calving event that was observed from satellite sensors in August 2010,shortening the ice tongue ...Petermann Glacier is a marine-terminating outlet glacier that had a 70 km-long floating ice tongue prior to a ～ 270 km2 calving event that was observed from satellite sensors in August 2010,shortening the ice tongue by ～ 27 km.Further,in July 2012,another 10 km was lost through calving.In order to understand these events in perspective,here the authors perform a long-term data analysis of Petermann Glacier calving-front variability and ice velocity for each year in the 1990s-2000s,supplemented by available observations from the previous three decades.Five major （on the order of 100 krm2） calving events are identified,with ～ 153 km2 calved from 1959 to 1961,～ 168 km2 in 1991,～ 71 km2 in 2001,～ 270 km2 in 2010,and ～ 130 km2 in 2012-as well as ～ 31 k m2 calved in 2008.The increased frequency of major calving events in recent years has left the front terminus position retreated nearly 25 km beyond the range of observed in previous decades.In contrast,stable ice-dynamics are suggested from ice-velocity measurements made each year between 1993-2012,which are on average 1063 m yr-1,with limited interannual variability and no significant trend; moreover,there is no apparent relationship between ice-velocity variability and calving events.The degree to which the massive calving events in 2010 and 2012 represent natural episodic variability or a response to atmospheric and/or oceanic changes remains speculative; however,melt-induced weakening of the floating ice tongue in recent years is strongly suggested.展开更多
文摘Based on the in situ optical measurements in the Bohai Sea of China, which belongs to a typical case-2 water area, we studied the characteristics of DCM (deep chlorophyll maximum) such as its spatial distribution, vertical profile, etc. We found that when the depth of the chlorophyll maximum is comparatively small, even in turbid coastal water regions, there is always a good correlation between the concentrations of chlorophyll maximum and the satellite-received signals in blue-green spectral bands; the correlation is even better than that between the surface chlorophyll concentrations and the satellite-received signals. The strong correlation existing even in turbid coastal water regions indicates that an ocean color model to retrieve the concentration of DCM can be constructed for coastal waters if a comprehensive knowledge of the vertical distribution of chlorophyll concentration in the Bohai Sea of China is available.
基金supported by the Trond Mohn Donation to the Mohn-Sverdrup Center at the Nansen Center,the Research Council of Norway’s UK/Netherlands/Norway RAPID programthe project AWAKE under the Polish-Norwegian Research Fund(2009–2011)
文摘Petermann Glacier is a marine-terminating outlet glacier that had a 70 km-long floating ice tongue prior to a ～ 270 km2 calving event that was observed from satellite sensors in August 2010,shortening the ice tongue by ～ 27 km.Further,in July 2012,another 10 km was lost through calving.In order to understand these events in perspective,here the authors perform a long-term data analysis of Petermann Glacier calving-front variability and ice velocity for each year in the 1990s-2000s,supplemented by available observations from the previous three decades.Five major （on the order of 100 krm2） calving events are identified,with ～ 153 km2 calved from 1959 to 1961,～ 168 km2 in 1991,～ 71 km2 in 2001,～ 270 km2 in 2010,and ～ 130 km2 in 2012-as well as ～ 31 k m2 calved in 2008.The increased frequency of major calving events in recent years has left the front terminus position retreated nearly 25 km beyond the range of observed in previous decades.In contrast,stable ice-dynamics are suggested from ice-velocity measurements made each year between 1993-2012,which are on average 1063 m yr-1,with limited interannual variability and no significant trend; moreover,there is no apparent relationship between ice-velocity variability and calving events.The degree to which the massive calving events in 2010 and 2012 represent natural episodic variability or a response to atmospheric and/or oceanic changes remains speculative; however,melt-induced weakening of the floating ice tongue in recent years is strongly suggested.
