scholarly journals Sea Ice Extent Detection in the Bohai Sea Using Sentinel-3 OLCI Data

2019 ◽  
Vol 11 (20) ◽  
pp. 2436 ◽  
Author(s):  
Hua Su ◽  
Bowen Ji ◽  
Yunpeng Wang
Keyword(s):  
Sea Ice ◽  
Bohai Sea ◽  
Regional Climate ◽  
Regional Climate Change ◽  
The Novel ◽  
Sea Ice Extent ◽  
Important Indicator ◽  
The Bohai Sea ◽  
Information Index ◽  
Ice Conditions

Sea ice distribution is an important indicator of ice conditions and regional climate change in the Bohai Sea (China). In this study, we monitored the spatiotemporal distribution of the Bohai Sea ice in the winter of 2017–2018 by developing sea ice information indexes using 300 m resolution Sentinel-3 Ocean and Land Color Instrument (OLCI) images. We assessed and validated the index performance using Sentinel-2 MultiSpectral Instrument (MSI) images with higher spatial resolution. The results indicate that the proposed Normalized Difference Sea Ice Information Index (NDSIIIOLCI), which is based on OLCI Bands 20 and 21, can be used to rapidly and effectively detect sea ice but is somewhat affected by the turbidity of the seawater in the southern Bohai Sea. The novel Enhanced Normalized Difference Sea Ice Information Index (ENDSIIIOLCI), which builds on NDSIIIOLCI by also considering OLCI Bands 12 and 16, can monitor sea ice more accurately and effectively than NDSIIIOLCI and suffers less from interference from turbidity. The spatiotemporal evolution of the Bohai Sea ice in the winter of 2017–2018 was successfully monitored by ENDSIIIOLCI. The results show that this sea ice information index based on OLCI data can effectively extract sea ice extent for sediment-laden water and is well suited for monitoring the evolution of Bohai Sea ice in winter.

scholarly journals Monitoring the Characteristics of the Bohai Sea Ice Using High-Resolution Geostationary Ocean Color Imager (GOCI) Data

2019 ◽  
Vol 11 (3) ◽  
pp. 777 ◽  
Author(s):  
Yu Yan ◽  
Kaiyue Huang ◽  
Dongdong Shao ◽  
Yingjun Xu ◽  
Wei Gu
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Bohai Sea ◽  
Ocean Color ◽  
High Temporal Resolution ◽  
The Bohai Sea ◽  
Ice Conditions ◽  
Ice Disaster

Satellite remote sensing data, such as moderate resolution imaging spectroradiometers (MODIS) and advanced very high-resolution radiometers (AVHRR), are being widely used to monitor sea ice conditions and their variability in the Bohai Sea, the southernmost frozen sea in the Northern Hemisphere. Monitoring the characteristics of the Bohai Sea ice can provide crucial information for ice disaster prevention for marine transportation, oil field operation, and regional climate change studies. Although these satellite data cover the study area with fairly high spatial resolution, their typically limited cloudless images pose serious restrictions for continuous observation of short-term dynamics, such as sub-seasonal changes. In this study, high spatiotemporal resolution (500 m and eight images per day) geostationary ocean color imager (GOCI) data with a high proportion of cloud-free images were used to monitor the characteristics of the Bohai Sea ice, including area and thickness. An object-based feature extraction method and an albedo-based thickness inversion model were used for estimating sea ice area and thickness, respectively. To demonstrate the efficacy of the new dataset, a total of 68 GOCI images were selected to analyze the evolution of sea ice area and thickness during the winter of 2012–2013 with severe sea ice conditions. The extracted sea ice area was validated using Landsat Thematic Mapper (TM) data with higher spatial resolution, and the estimated sea ice thickness was found to be consistent with in situ observation results. The entire sea ice freezing–melting processes, including the key events such as the day with the maximum ice area and the first and last days of the frozen season, were better resolved by the high temporal-resolution GOCI data compared with MODIS or AVHRR data. Both characteristics were found to be closely correlated with cumulative freezing/melting degree days. Our study demonstrates the applicability of the GOCI data as an improved dataset for studying the Bohai Sea ice, particularly for purposes that require high temporal resolution data, such as sea ice disaster monitoring.

scholarly journals Sea-Effect Precipitation over the Shandong Peninsula, Northern China

2018 ◽  
Vol 57 (6) ◽  
pp. 1291-1308 ◽  
Author(s):  
Baoleerqimuge Bao ◽  
Guoyu Ren
Keyword(s):  
Sea Ice ◽  
Bohai Sea ◽  
Gravitational Instability ◽  
Lower Troposphere ◽  
Northern China ◽  
Significant Negative Correlation ◽  
Sea Ice Extent ◽  
Shandong Peninsula ◽  
Cold Air ◽  
The Bohai Sea

AbstractSea-effect precipitation (SEP) over the Shandong Peninsula is a unique climatological phenomenon in mainland China, and it exerts a considerable impact on the southern shore of the Bohai Sea. From observed data from 123 stations for the period 1962–2012, the characteristics of cold-season (November–February) SEP in this area were analyzed. Results showed that SEP occurred throughout the late autumn and winter. In all, 1173 SEP days were identified during the 51 years, of which snow days accounted for 73.7% and rain and snow–rain days accounted for 16.1% and 10.1%, respectively. December had the largest number of SEP snow days, followed by January and November. November was the most productive month in terms of SEP rain and snow–rain days. Intense SEP snowfall mainly affected the inland hill area of the peninsula, whereas light SEP snowfall reached farther inland. SEP rainfall shared a similar pattern with snowfall. The SEP frequency showed a significant interannual variability and a nonsignificant upward trend over the period analyzed. SEP was most likely to occur when the temperature difference between sea surface and 850 hPa over the Bohai Sea was above 10°C, indicating a dominant influence of low-level cold-air advection over the sea on the generation and development of the weather phenomenon. A significant negative correlation was also found between the area of sea ice in the Bohai Sea and intense SEP snowfall, indicating that sea ice extent had an important effect on SEP variability over the peninsula. In the case of extremely intense SEP events, a deeper East Asian trough at the 500-hPa level developed over the southwest of the study area and temperature and geopotential height contours were orthogonal to each other, indicating strong geostrophic cold-air advection over the Bohai Sea and the Shandong Peninsula. The extremely intense SEP events were also characterized by anomalous low temperature and high relative humidity in the lower troposphere, which contributed to greater gravitational instability in the study area.

scholarly journals Long-Term Ice Conditions in Yingkou, a Coastal Region Northeast of the Bohai Sea, between 1951/1952 and 2017/2018: Modeling and Observations

2022 ◽  
Vol 14 (1) ◽  
pp. 182
Author(s):  
Yuxian Ma ◽  
Bin Cheng ◽  
Ning Xu ◽  
Shuai Yuan ◽  
Honghua Shi ◽  
...  
Keyword(s):  
Sea Ice ◽  
Air Temperature ◽  
Large Scale ◽  
Bohai Sea ◽  
Coastal Region ◽  
Ice Thickness ◽  
Climate Indices ◽  
Clear Trend ◽  
The Bohai Sea ◽  
Ice Conditions

Bohai Sea ice creates obstacles for maritime navigation and offshore activities. A better understanding of ice conditions is valuable for sea-ice management. The evolution of 67 years of seasonal ice thickness in a coastal region (Yingkou) in the Northeast Bohai Sea was simulated by using a snow/ice thermodynamic model, using local weather-station data. The model was first validated by using seasonal ice observations from field campaigns and a coastal radar (the season of 2017/2018). The model simulated seasonal ice evolution well, particularly ice growth. We found that the winter seasonal mean air temperature in Yingkou increased by 0.33 °C/decade slightly higher than air temperature increase (0.27 °C/decade) around Bohai Sea. The decreasing wind-speed trend (0.05 m/s perdecade) was a lot weaker than that averaged (0.3 m/s per decade) between the early 1970s and 2010s around the entire Bohai Sea. The multi-decadal ice-mass balance revealed decreasing trends of the maximum and average ice thickness of 2.6 and 0.8 cm/decade, respectively. The length of the ice season was shortened by 3.7 days/decade, and ice breakup dates were advanced by 2.3 days/decade. All trends were statistically significant. The modeled seasonal maximum ice thickness is highly correlated (0.83, p < 0.001) with the Bohai Sea Ice Index (BoSI) used to quantify the severity of the Bohai Sea ice condition. The freezing-up date, however, showed a large interannual variation without a clear trend. The simulations indicated that Bohai ice thickness has grown continuously thinner since 1951/1952. The time to reach 0.15 m level ice was delayed from 3 January to 21 January, and the ending time advanced from 6 March to 19 February. There was a significant weakening of ice conditions in the 1990s, followed by some recovery in 2000s. The relationship between large-scale climate indices and ice condition suggested that the AO and NAO are strongly correlated with interannual changes in sea-ice thickness in the Yingkou region.

scholarly journals Anomalous blocking over Greenland preceded the 2013 extreme early melt of local sea ice

2017 ◽  
Vol 59 (76pt2) ◽  
pp. 181-190 ◽  
Author(s):  
Thomas J. Ballinger ◽  
Edward Hanna ◽  
Richard J. Hall ◽  
Thomas E. Cropper ◽  
Jeffrey Miller ◽  
...  
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Circulation Pattern ◽  
The Arctic ◽  
Labrador Sea ◽  
First Year ◽  
Tropospheric Circulation ◽  
Blocking Index

ABSTRACTThe Arctic marine environment is undergoing a transition from thick multi-year to first-year sea-ice cover with coincident lengthening of the melt season. Such changes are evident in the Baffin Bay-Davis Strait-Labrador Sea (BDL) region where melt onset has occurred ~8 days decade−1 earlier from 1979 to 2015. A series of anomalously early events has occurred since the mid-1990s, overlapping a period of increased upper-air ridging across Greenland and the northwestern North Atlantic. We investigate an extreme early melt event observed in spring 2013. (~6σ below the 1981–2010 melt climatology), with respect to preceding sub-seasonal mid-tropospheric circulation conditions as described by a daily Greenland Blocking Index (GBI). The 40-days prior to the 2013 BDL melt onset are characterized by a persistent, strong 500 hPa anticyclone over the region (GBI >+1 on >75% of days). This circulation pattern advected warm air from northeastern Canada and the northwestern Atlantic poleward onto the thin, first-year sea ice and caused melt ~50 days earlier than normal. The episodic increase in the ridging atmospheric pattern near western Greenland as in 2013, exemplified by large positive GBI values, is an important recent process impacting the atmospheric circulation over a North Atlantic cryosphere undergoing accelerated regional climate change.

scholarly journals Spatio-temporal characteristics of the sea-ice volume of the Bohai Sea, China, in winter 2009/10

2013 ◽  
Vol 54 (62) ◽  
pp. 97-104 ◽  
Author(s):  
Chengyu Liu ◽  
Wei Gu ◽  
Jinlong Chao ◽  
Lantao Li ◽  
Shuai Yuan ◽  
...  
Keyword(s):  
Sea Ice ◽  
Bohai Sea ◽  
Shortwave Radiation ◽  
Laizhou Bay ◽  
Bohai Bay ◽  
Temporal Characteristics ◽  
The Bohai Sea ◽  
Ice Volume ◽  
Radiation Theory ◽  
Spatio Temporal

AbstractTo investigate the spatio-temporal characteristics of sea-ice resource, we used sea-ice volume to measure the amount of sea-ice resource in the Bohai Sea, China. The sea-ice area was extracted from Advanced Very High Resolution Radiometer (AVHRR) remote-sensing images using the zonal threshold method. The sea-ice thickness was estimated using a sea-ice model based on shortwave radiation theory and field measurements. The spatio-temporal characteristics of sea-ice volume were then analysed using GIS technology. The results indicate that the Bohai Sea experienced two sea-ice volume peaks in winter 2009/10. The largest sea-ice volume was in Liaodong Bay (∼80.26% of the entire sea-ice volume of the Bohai Sea). Bohai Bay had the second largest ice volume, and Laizhou Bay the smallest. The relationship between sea-ice volume and distance from shore is essentially exponential. The proportion of total sea-ice volume that is 0–10 km from shore is ∼42.43%, whereas the proportion that is 100–110 km from shore is only 0.002%.

The spatiotemporal patterns of sea ice in the Bohai Sea during the winter seasons of 2000–2016

2017 ◽  
Vol 12 (8) ◽  
pp. 893-909 ◽  
Author(s):  
Lunxi Ouyang ◽  
Fengming Hui ◽  
Lixian Zhu ◽  
Xiao Cheng ◽  
Bin Cheng ◽  
...  
Keyword(s):  
Sea Ice ◽  
Bohai Sea ◽  
Spatiotemporal Patterns ◽  
The Bohai Sea

scholarly journals 50 years of ice-front changes between the Adélie and Banzare Coasts, East Antarctica

2002 ◽  
Vol 34 ◽  
pp. 235-240 ◽  
Author(s):  
Massimo Frezzotti ◽  
Marco Polizzi
Keyword(s):  
Climate Change ◽  
Satellite Images ◽  
Regional Climate ◽  
Regional Climate Change ◽  
East Antarctica ◽  
Sea Ice Extent ◽  
Wilkes Land ◽  
Fast Ice ◽  
Cyclical Behaviour ◽  
General Reduction

AbstractIce-front change may well be a sensitive indicator of regional climate change. We studied the coastal sector of Wilkes Land, East Antarctica, along the Adélie and Banzare Coasts, extending from Buchanan Bay (67°05’ S, 144°30’ E) to Porpoise Bay (67°S, 128°E). The glaciers in this area drain the northern part of Dome C (area 270 000 km2). A comparison of maps, photographs and satellite images, dated several years apart, led to an estimation of the fluctuations of 18 ice fronts over the 50 years 1947–97 .The area of the floating glaciers in 1963 was 3035 km2, and in 1989, 2785 km2. The main glaciers in the area are Zélée, Astrolabe, du Français, Commandant Charcot and Pourquoi Pas for the Adélie Coast, and Dibble, May, Sandford and Frost Glaciers for the Clarie and Banzare Coasts. Most of the floating glaciers have shown cyclical behaviour without a marked trend, but a general reduction since 1947. The reduction in the area of floating glaciers since the 1950s may be linked to changes in ice–ocean interaction, as noted for the floating glaciers of the George V Coast and the Cape Adare area, and sea-ice extent. The calving behaviour of the main glacier tongues is characterized by an accumulation of icebergs projecting from the coast to form iceberg tongues, held in place by grounding and joined together by annual or perennial fast ice.

Spectral reflection characteristics of sea ice polluted by pulverized coal in the Bohai Sea

2020 ◽  
Vol 21 (2) ◽  
pp. 157-166
Author(s):  
Chunjiang Bai ◽  
Ying Li ◽  
Bingxin Liu ◽  
Chengyu Liu ◽  
Feng Xie
Keyword(s):  
Sea Ice ◽  
Bohai Sea ◽  
Pulverized Coal ◽  
Spectral Reflection ◽  
The Bohai Sea ◽  
Reflection Characteristics
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