Personnel: Professors Hongjie Xie and Steve Ackley, PhD student Wentao Xia

Dr. Hongjie Xie was invited to attend the 4th Chinese Arctic Expedition (Xuelong or Snow Dragon) to study Arctic sea ice (July 1 to Sept 20, 2010), the most impacted one due to global warming. This is the first time that the LRSG/UTSA extends its sea ice study from Antarctic to Arctic and the third time that LRSG participates a ship-based polar expedition to collect rich sea ice geophysical data and for validation of satellite-derived geophysical products. The participation gives LRSG an unprecedented opportunity to collaborate with Chinese scientists for polar study. Xie's participation was partially supported by NOAA's Climate Research/Sea Ice Outlook Program and the NASA project (#NNX08AQ87G). During the trip, Dr. Xie reported the sea ice observations to the Arctic Sea Ice Outlook program through Dr. Jenny Hutchings at the University of Alaska Fairbanks. 

The most north point the Xuelong Icebreaker reached was 88°26.52'N/176°59.88'W. This indeed reflects the significance of Arctic sea ice melting and thinning due to global warming, it was otherwise impossible for Xuelong to reach this high latitude. One of the big achievements of the cruise for the Chinese is that, for the first time, China utilized its own ship and helicopter to reach the polar point and conduct drilling, CTD, water samples, and other scientific activities in the polar point.

Figure 1. The Xuelong Icebreaker and 121 persons on the ship (at the Long-term ice station), 8/17/2010

    

Figure 2. The waving Chinese flag and team flag on the polar point, 8/20/2010

Figure 3. The cruise starts from Xianmen (July 1) and ends at Shanghai (Sept 20), a total 23,335 km.

Figure 4. Locations of 8 short-term ice station (IS) and date (MMDD) and one long-term ice station (LIS) and date (MMDD) conducted in the cruise. Ice was first seen at 69.8N on July 21 and last seen at 75.6N on August 28.

News reports about Dr. Xie and the cruise

• Dr. Xie and Dr. Ke from Nanjing University measuring solar radiation on the Xuelong, July 12, 2010 (link)

• Dr. Xie talks about the interesting dirty ice on July 25, 2010 (link)

• Dr. Xie reports his trip in the China University of Geosciences, Beijing (CUG) and donates a bottle of water collected at the Polar Point to the CUG Museum on Sept 15, 2010 (link)

　

• Dr. Xie's Arctic expedition on UTSA TODAY news, November 30, 2010 (link)

　

• Dr. Xie's Arctic expedition on Texas Public Radio, December 7, 2010 (link)

• Dr. Xie's Arctic expedition on KENS5 news, December 17, 2010 (link)

• Dr. Xie's Arctic expedition on UTSA Paisano News, Jan 16, 2011 (link)

• Dr. Xie's Arctic expedition on UTSA College of Sciences CATALYST, summer 2011 (link)

• Dr. Xie's Arctic expedition on UTSA Discovery Magzine, Dec 2011 (link)

　

　

Publications

　

Summer Sea ice in the Pacific Arctic sector from the CHINARE-2010 cruise

Hongjie Xie 1, Ruibo Lei 2, Wenfeng Huang 3, Changqing Ke 4, Zhijun Li 3, Steve Ackley 1, and the Sea Ice Team of the cruise
　

1 Laboratory for Remote Sensing and Geoinformatics, University of Texas at San Antonio, Texas, 78249, USA
2 Polar Research Institute of China, Shanghai, 200136, China
3 State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, 116024, China
4  School of Geographic & Oceanographic Sciences, Nanjing University, Nanjing, 210093, China


The Fourth Chinese National Arctic Research Expedition (CHINARE) from July 1 to Sep. 20, 2010, the last Chinese campaign in Arctic Ocean contributing to the fourth International Polar Year (IPY), conducted comprehensive scientific studies on ocean-ice-atmosphere interaction and the marine ecosystem’s response to climatic change in Arctic. This paper presents an overview on sea ice (ice concentration, floe size, melt pond coverage, sea ice and snow thickness) of the Pacific Arctic sector, in particular between 150°W to 180°W to 88.5°N, based on (1) underway visual observations of sea ice at half-hourly and automatic camera recording (side looking in both starboard sides of the R.V. Xuelong) every 10 to 15 seconds; (2) a downward-looking video mounted on the left port side of the Xuelong at a height of 7 m above waterline recording overturning of ice floes; (3) on-site measurements of snow and ice thickness using drilling and electromagnetic instrument EM31 (9.8 kHz) at eight short-term (~3 hours each) and one 12-day ice stations; (4) six flights of aerial photogrammetry from helicopter, and (5) Satellite data (AMSE-E ice concentration, ENVISAT ASAR, and NIC ice charts) that extended the observations/measurements along the ship track and airborne flights. In the northward leg,  the largest ice concentration zone was in the area starting from ~75°N (July 29), with ice concentration of 60-90% (mean ~80%), ice thickness of 1.5-2m, melt ponds of 10-50% of ice, ridged ice of 10-30% of ice,  and floe size of 100's m to kms. The 12-day ice station (from Aug 7-19), started at 86.92°N/178.88°W and drifted a total of 175.7km, was on an ice floe over 100 km2 in size and ~2 m in mean thickness. There were two heavy and several slight snowfall events in the period (July 29 to Aug 19). Snow thickness varies from 5cm to 15 cm, and melted about 5cm during the 12-day ice camp.  In the southward leg, the largest sea ice concentration zone was in the area between 87°N to 80°N (from August 21 to August 24). In this area, the ice concentration varied from 70-100%, melt pond varied from 20-50% of ice, ridged ice varied from 10-30% of ice, and floe size was dominated by 10’s km to several km’s in one or two dimensions. The overall ice thickness decrease southwards from 1.8-2m to 0.6-1m. The ice type of the area was multiyear ice dominated, with small portion of first year ice.  In the area from ~85°N to 83.5°N, we saw dirty ice (brownish, rich hills and valleys, mostly multiyear ice), varying from 10-20% of ice. Similar dirty ice was only seen 72°N-75°N in the northward leg (July 24-29). The ice situation in this cruise will be compared with that from the CHINARE-2008 cruise, in the similar area and season, so change of the two years for this sector of Arctic Ocean during the middle-later summer can be deduced.

(Acknowledgements: The study was partially supported by the NASA grant (#NNX08AQ87G), the Chinese NSF grant (#40930848), and the Norwegian grant (#193592/S30). Travel expenses for H. Xie were covered by the NOAA's Climate Research/Sea Ice Outlook Program. We sincerely acknowledge the supports from the Chinese Arctic and Antarctic Administration and the The fourth Chinese Arctic Expedition Team)

　

Summer Sea ice thickness in the Pacific Arctic sector from the CHINARE-2010 cruise: A potentially valuable dataset for Cal/Val of CryoSat sea ice thickness estimation

Hongjie Xie 1, Changqing Ke 2, Ruibo Lei 3, Jinping Zhao 4, Zhijun Li 5, Steve Ackley 1, and the Sea Ice Team of the cruise
　

1 Laboratory for Remote Sensing and Geoinformatics, University of Texas at San Antonio, Texas, 78249, USA,  2 School of Geographic & Oceanographic Sciences, Nanjing University, Nanjing, 210093, China
3 Polar Research Institute of China, Shanghai, 200136, China

4 College of Physical and Environmental Oceanography, Ocean University of China, Qingdao, 261000, China
5 State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, 116024, China

The Fourth Chinese National Arctic Research Expedition (CHINARE) from July 1 to Sep. 20, 2010, conducted ocean-ice-ecosystem-atmosphere study in the Pacific Arctic sector, in particular between 150°W to 180°W to 88.5°N. Sea ice thickness measurements were performed at 8 short-term ice stations and one long-term ice station using electromagnetic induction sounding (EM31). The EM-estimated thicknesses were compared with borehole-drilling thicknesses. The error found is between 3-7%. In each short-term ice station, one or more profiles covering the work zone were surveyed with a fixed sampling interval of approximately one meter (two steps). In the long-term ice station (~86°50’N-87°20’N), a grid of 8 profiles of 100 meters in work zone 2 and two other profiles (200m and 125m) in work zone 3 were surveyed with repeat intervals of 3 to 4 days. A mean of 1.8cm per day in ice melting (primarily bottom melting) was obtained at the long-term station from Aug 10-19. The mean sea ice thickness at the long-term ice station was ~1.8m, while it was from 1.2-2.1m for the 8 short-term ice stations. Those thicknesses data are valuable in calibrating/validating Cryosat sea ice thickness, if available for the time and for the region.

(Acknowledgements: The study was partially supported by the NASA grant (#NNX08AQ87G) and the Chinese NSF grant (#40930848). Travel expenses for H. Xie were covered by the NOAA's Climate Research/Sea Ice Outlook Program. We sincerely acknowledge the supports from the Chinese Arctic and Antarctic Administration and the The fourth Chinese Arctic Expedition Team)