Chinese investigation and research in Southern Ocean physical oceanography and meteorology during the Chinese Polar Programs 2011–2015

Within the context of developing a research presence in the Antarctic region, the first phase of the Chinese Polar Programs covered the period 2011-2015, which almost coincided with the 12th Five-Year Plan （2011-2015）. For the promotion of full understanding of the progress of Chinese expeditions and research in Antarctica, the observations and achievements of cruises during 2011-2015 are summarized in this paper. Four Antarctic cruises （28th-31st） were performed in the Prydz Bay and Antarctic Peninsula regions during the first phase of the Polar Programs. These cruises performed systemic collections of physical oceanographic and meteorological data to support further research on the ice-ocean-atmosphere interactions in Antarctica. Overall, 248 CTD/LADCP stations, 66 microstructure profiles, 507 XBT/XCTDs, 181 air sounding balloons, 58000 total gaseous mercury （TGM） concentrations, 452 aerosol samples, 294 atmospheric samples, 11 moorings, and 28 surface drifters were acquired or deployed during the four cruises. Using these extensive observations and other data, Chinese scientists have achieved new recognition in the fields of Southern Ocean physical oceanography and meteorology, as well as in other interdisciplinary subjects. These studies, which have been associated with scientific techniques, instrumentation, ocean circulation, water mass formation, energy transformation, and carbon uptake, have elucidated the dynamic mechanisms and potential effects of climate change in Antarctica. Finally, some observations based on experience gained during previous Chinese Antarctic Research and Expedition campaigns are summarized with advice for the improvement of future investigations in the Antarctic region.

Progress of Chinese research in Arctic physical oceanography during 2007-2010

As a part of the National Report of China for the International Association for Physical Science of Ocean （IAPSO）, the main research results of Chinese scientists in Arctic physical oceanography during 2007-2010 are reviewed in this paper. This period overlaps with the International Polar Year （IPY）, which is a catalyst for nations to emphasize activities and research in the polar regions. The Arctic also experienced a rapid change in sea ice, ocean, and climate during this time. China launched two Arctic cruises with the R/V XUE LONG icebreaker, in 2008 and 2010, which provided more opportunities for Chinese scientists to investigate the Arctic Ocean and its change. During this period, Chinese scientists participated in more than ten other cruises with international collaborations. The main research covered in this paper includes the upper ocean characteristic, ocean and sea ice optics, kinematics of sea ice and the Arctic impact on global climate change. The progress in sea ice optics, the observation technologies and Arctic Oscillation are especially remarkable.

Progress in Chinese research on water masses and circulation in the Arctic and subarctic ocean

The Arctic Ocean and Arctic sea ice have undergone a series of rapid changes. Oceanographic surveying has become one of the key missions of the Chinese National Arctic Research Expeditions since 1999. Using the data obtained in these surveys and from other sources, Chinese researchers have carried out a series of studies in the field of Arctic physical oceanography. The Near Sea-surface Temperature Maximum, freshwater content and heat flux in different regions of the Arctic have drawn wide attention from Chinese researchers. Arctic circulation is changing with the decline of sea ice, which is also influencing the structure and distribution of water masses. Studies have also focused on these issues. In this paper, the main results of research on water masses, currents, the structure of the upper ocean and other major hydrological phenomena over the past two decades are summarized.

The SOOS Asian Workshop on Southern Ocean research and observations

1 Background and purpose of workshop The Southern Ocean plays a fundamental role in the function of the Earth System, influencing climate, sea level, biogeochemical cycles, and biological productivity on a variety of scalesIll. Observations from the Southern Ocean suggest that dramatic changes are taking place, which are of global concern, yet because of its remote location, seasonal sea ice, and harsh environment, the Southern Ocean remains one of the least sampled zones in the world.

Sampling errors of the global mean sea level derived from TOPEX/Poseidon altimetry

Sampling errors of the global mean sea level derived from TOPEX/Poseidon （T/P） altimetry are explored using 31/ 4a of eddy-resolving numerical model outputs for sea level. By definition, the sampling errors would not exist if data were available everywhere at all times. Four problems with increasing and progressively added complexities are examined to understand the causes of the sampling errors. The first problem （P1） explores the error incurred because T/P with turning latitudes near 66° latitudes does not cover the entire globe. The second problem （P2） examines, in addition, the spatial sampling issue because samples are only available along T/P ground tracks. The third problem （P3） adds the additional complexity that sea level at any along track location is sampled only once every 10 d versus every 3 d for the model （i.e., the temporal sampling issue）. The fourth problem （P4） incorporates the full complexity with the addition of real T/P data outages. The numerical model （Los Alamos POP model Run 11） conserves the total water volume, thus generating no global mean sea level variation. Yet when the model sea level is sampled in the four problems （with P4 using the real T/P sampling）, variations occur as manifestations of the sampling errors. The results show root-mean-squares （rms） sampling errors for P1 of 0.67 （0.75） mm for 10 d （3 d） global mean sea level, 0.78 （0.86） mm for P2, 0.79 mm for P3, and 1.07 mm for P4, whereas the amplitudes of the sampling errors can be as large as 2.0 （2.7） mm for P1, 2.1 （2.7） mm for P2, 2.2 mm for P3, and 2.5 mm for P4. The results clearly show the largest source of the sampling errors to be the lack of global coverage （i.e., P1）, which the model has actually underestimated due to its own less-than-global coverage （between latitudes about 77° latitudes）. We have extrapolated that a truly global model would show the rms sampling error to be 1.14 （1.28） mm for P1, thus implying a substantially larger sampling error for P4.