Ship based measurements on sea ice morphology during the CHINARE Antarctic and Arctic cruises

Transcription

1 Ship based measurements on sea ice morphology during the CHINARE Antarctic and Arctic cruises Ruibo Lei Council of COMNAP Workshop Sea Ice Challenges 13 May,2014, Hobart, Tasmania, Australia

2 Outline 1. Overview of CHINARE Antarctic and Arctic cruises 2. Objectives of ship-based measurements 3. System of ship-based measurements 4. Case study 5. Limitations and prospects

3 1. Overview of CHINARE Antarctic and Arctic cruises Chinese National Arctic/Antarctic Research Expeditions (CHINARE) 31 National Antarctic Research Expeditions since National Arctic Research Expeditions with icebreaker R/V Xuelong in 1999, 2003, 2008, 2010 and years of expeditions with Arctic Yellow River Station at Svalbard since 2004.

4 Antarctic cruises Key region1: Prydz Bay Key region2: Ross sea

5 Arctic cruises 90 o N Some people took part in cruises organized by other country 70 o N CHINARE-1999 Arctic cruise organized by The SOA of China 75 o N 80 o N 85 o N Yellow River Station sut up in Ny-Ålesund 2004 CHINARE-2010 Arctic cruise AOS94(26 Jul.-22 Aug.) HOTRAX05(9 Aug.-7 Sep.) St.Laurent06(7 Aug.-2 Sep.) CHINARE-2014 Arctic cruise CHINARE08(3-20 Aug.) CHINARE10(24 Jul.-19 Aug.) St.Laurent12(8-26 Aug.) CHINARE14(1-17 Aug.) IPY Challenge increase <=> Activity increase + Sea ice change 125 o E A Chinese team explored from 88ºN to 90ºN under the nongovernmental fund o E CHINARE-2003 Arctic cruise 175 o E CHINARE- 2008Arctic cruise 160 o W 海冰密集度成 135 o W CHINARE-2012 Arctic cruise / Go through the NEP Sea ice concentration /tenth

6 2 Objectives of ship-based measurements 2.1 Provide near real time in-situ data to interpret remote sensing image; then through combining both data sets can benefit the ship operation. From 3.125km AMSR2 data, we cannot identify what is the state of ice condition? From ship-based observations, associated with aerial investigation, we can character the ice as following: Concentration: ~95%; Thickness: for level ice ~1.5m; Melt pond coverage: ~20% over ice Ridge: heavy, ~30% deformed ice Floe size: m

7 2 Objectives of ship-based measurements 2.2 To validate and supplement the remote sensing data The data has been used to validate the data of ice concentration derived from SSMI, AMSR-E, AMSR2 using the NASA-team (NT), bootstrap (BST) and ASI algorithms. Due to the surface melt, the quality of ice thickness data derived from CryoSat2 is low during the summer. The remote sensing data only can be used to initialize the numerical sea ice prediction system after validation with the in-situ data.

8 2 Objectives of ship-based measurements 2.3 The data of snapshot observations onboard the ship in the same region can used to quantify the long-term changes in sea ice conditions o N 90 o N o E 70 o N 75 o N 80 o N AOS94(26 Jul.-22 Aug.) HOTRAX05(9 Aug.-7 Sep.) St.Laurent06(7 Aug.-2 Sep.) CHINARE08(3-20 Aug.) CHINARE10(24 Jul.-19 Aug.) St.Laurent12(8-26 Aug.) CHINARE14(1-17 Aug.) 135 o W Latitude / N 纬度 / ( N) o E 175 o E o W 海冰密集度 / 成 Sea ice concentration /tenth Jul. 8 Sep. / 20Jul. 8 Sep. / 20Jul. 8 Sep. / 20Jul. 8 Sep. / 20Jul. 8 Sep. / 20Jul. 8 Sep. / 20Jul. 8 Sep 期

9 3. System of ship-based measurements thermometers Spectral albedo measurement

10 EM31-ICE for ice thickness measurements Antenna for data transmission GPS ~3.8m ~8m EM31-ICE Laser Sonic sensor Real-time displayed data Tilt sensor Lad test Fiberglass-reinforced frame

11 4. Case study Antarctica During the summer of

12 4. Case study Antarctica 总反照率 Albedo Albedo Ct=C1+C2+C3+ αt =α1*c1+α2*c2+α3*c3 Li, Lei et al., 2015 总反照率 总反照率 Albedo ' Albedo 总反照率 总反照率 AMSR-2 密集度 Latitude/ 纬度 / S S 总反照率 AMSR-2 密集度 月 30 日 12 月 1 日 12 月 2 日 12 月 3 日 67.0 Albedo Ship AMSR2 30 Nov 1 Dec Dec 月 1 日 Latitude/ S 纬度 / S 2 月日 1 Mar 28 Feb AMSR-2 密集度人工观测密集度总反照率 纬度 / S 12 月 21 日 Latitude/ S 12 月 20 日 12 月 19 日 21 Dec 20 Dec 19 Dec Latitude/ 纬度 / S S 26 Feb 27 Feb 2 月 26 日 2 月 27 日 AMSR-2 密集度人工观测密集度总反照率 Dec Concentration/% 密集度 /% Concentration/% 密集度 Concentration/% 密集度 /% Concentration/% 密集度

13 Lei et al., 2008

14 Island Iceberg

15 4. Case study Arctic From AMSR_E+AMSR2

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17 78 o N Open water Ponded ice Sea ice (snow cover or bare) 80 o N F8 176 o W 82 o N 84 o N 3% < 1% 97% 86 o N 83% F8 5 Sep. F7 168 o W F7 4 Sep. 14% 5% F3 32% 11% 17% < 1% F5 12% 19% 81% F5 30 Aug. F4 20 Aug. 36% F6 31 Aug. 160 o W 57% 50% F3 19 Aug. 9% F2 18 Aug. 42% F2 42% 152 o W 3% 10% F4 69% F1 17 Aug. 48% F1 F6 61% 144 o W Lei et al., 2012

18 纬度 /( N) Latitude 纬度 / N /( N) Case1: Ice+Water Case2: Ice+Melt pond+water Case1-Case 反照率 Albedo 纬度 /( N) Jul. 20 Jul. / 8 Sep. 20 Jul. / 8 Sep. 20 Jul. / 8 Sep. 20 Jul. / 8 Sep. 20 Jul. / 8 Sep. 20 Jul. / 8 Sep. 8 Sep 日期 Difference 反照率之差

19 Prior to use the ship-based data, the data has been compared with ice-based measurements

20 20' 10' 80 o N 50' 42.3km 24.7km 37.9km 36.6km 4 号冰站 39.4km 32.7km 22.4km 42.3km 47.8km 46.1km 35.0km 100.8km 40' 55.9km 70.6km 5 号冰站 84.8km 45.1km 30' 20' 10' 78 o N (a) (b) 156 o W 30' 162 o W 160 o W 158 o W 163 o W 161 o W 159 o W 30.3km 25.8km (c) (d) 157 o W (e) 15' 10' 5' 81 o N 55' 12' 6' 81 o N 54' 48' 42' 36' 158 o W 157 o W 156 o 159 o W W 158 o W 24' 18' 20.3km 17.2km 31.5km 12' 6' 20.0km 长期冰站 25.4km 18.8km 20.6km 长期冰站 46.3km 48.1km 34.7km 49.0km 26.7km 6 号冰站 42.1km 39.4km 80 o N 54' 154 o W 153 o W 海冰速度 (m/s) 0 29 Aug. 8 Sep. 18 Sep. 28 Sep. 8 Oct. 18 Oct. 28 Oct. 7 Nov. 17 Nov. 27 Nov 纬度 / N 144 o W o W 150 o W 海冰速度 /(m/s) Aug. 8 Sep. 18 Sep. 28 Sep. 8 Oct. 18 Oct. 28 Oct. 7 Nov. 17 Nov. 27 Nov. 日期 Drift speed 162 o W 82 o N 81 o N 80 o N 79 o N 78 o N 77 o N 76 o N 168 o W

21 5. Limitations I. Due to the heavy logistical mission for Antarctic stations, the time for marine survey in South Ocean is very limited. To save the time and for the save of the ship, the Captain intensively prefer leads/open water, but not the ice zone. II. Due to the relatively low level of ice-breaking of R/V Xuelong, the ship-based measurements only can be done during the summer. Ice stations cannot be set up during the summer, and the chance of ship navigating through the ice zone is also very limited. III.The CHINARE Antarctic Expedition range from marine cruise, station-based observation and inland investigation. Both ship-time and cabin are limited for sea ice scientists. (V.S. dedicated oceanography cruise in Arctic, we have 6-10 positions for the sea ice team)

22 5. Prospects Ice breaking capability of 1.5m sea ice plus 0.2m snow, at speed of 2 to 3 knots I. Probably dedicated oceanography cruise in Antarctica II. Probably winter cruise in Arctic and Antarctica III. More attentions will be given to field work on sea ice physics and the interactions with atmosphere and ocean

23 谢 谢!