The Fram Strait（FS） is the primary region of sea ice export from the Arctic Ocean and thus plays an important role in regulating the amount of sea ice and fresh water entering the North Atlantic seas. A 5 a（2011–2...The Fram Strait（FS） is the primary region of sea ice export from the Arctic Ocean and thus plays an important role in regulating the amount of sea ice and fresh water entering the North Atlantic seas. A 5 a（2011–2015） sea ice thickness record retrieved from Cryo Sat-2 observations is used to derive a sea ice volume flux via the FS. Over this period, a mean winter accumulative volume flux（WAVF） based on sea ice drift data derived from passivemicrowave measurements, which are provided by the National Snow and Ice Data Center（NSIDC） and the Institut Francais de Recherche pour d＇Exploitation de la Mer（IFREMER）, amounts to 1 029 km^3（NSIDC） and1 463 km^3（IFREMER）, respectively. For this period, a mean monthly volume flux（area flux） difference between the estimates derived from the NSIDC and IFREMER drift data is –62 km^3 per month（–18×10~6 km^2 per month）.Analysis reveals that this negative bias is mainly attributable to faster IFREMER drift speeds in comparison with slower NSIDC drift data. NSIDC-based sea ice volume flux estimates are compared with the results from the University of Bremen（UB）, and the two products agree relatively well with a mean monthly bias of（5.7±45.9） km^3 per month for the period from January 2011 to August 2013. IFREMER-based volume flux is also in good agreement with previous results of the 1990 s. Compared with P1（1990/1991–1993/1994） and P2（2003/2004–2007/2008）, the WAVF estimates indicate a decline of more than 600 km^3 in P3（2011/2012–2014/2015）. Over the three periods, the variability and the decline in the sea ice volume flux are mainly attributable to sea ice motion changes, and second to sea ice thickness changes, and the least to sea ice concentration variations.展开更多
We present a quantum adiabatic algorithm for a set of quantum 2-satisfiability(Q2SAT)problem,which is a generalization of 2-satisfiability(2SAT)problem.For a Q2SAT problem,we construct the Hamiltonian which is similar...We present a quantum adiabatic algorithm for a set of quantum 2-satisfiability(Q2SAT)problem,which is a generalization of 2-satisfiability(2SAT)problem.For a Q2SAT problem,we construct the Hamiltonian which is similar to that of a Heisenberg chain.All the solutions of the given Q2SAT problem span the subspace of the degenerate ground states.The Hamiltonian is adiabatically evolved so that the system stays in the degenerate subspace.Our numerical results suggest that the time complexity of our algorithm is O(n^(3.9))for yielding non-trivial solutions for problems with the number of clauses m=dn(n-1)/2(d■0.1).We discuss the advantages of our algorithm over the known quantum and classical algorithms.展开更多
基金The National Natural Science Foundation of China under contract No.41406215the Foundation of Laboratory for Marine Geology,Institute of Oceanology,Chinese Academy of Sciences+3 种基金the Foundation of Qingdao National Laboratory for Marine Science and Technologythe Postdoctoral Science Foundation of China under contract No.2014M561971the Open Fund for the Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences under contract No.MGE2013KG07the NSFC-Shandong Joint Fund for Marine Science Research Centers under contract No.U1606401
文摘The Fram Strait（FS） is the primary region of sea ice export from the Arctic Ocean and thus plays an important role in regulating the amount of sea ice and fresh water entering the North Atlantic seas. A 5 a（2011–2015） sea ice thickness record retrieved from Cryo Sat-2 observations is used to derive a sea ice volume flux via the FS. Over this period, a mean winter accumulative volume flux（WAVF） based on sea ice drift data derived from passivemicrowave measurements, which are provided by the National Snow and Ice Data Center（NSIDC） and the Institut Francais de Recherche pour d＇Exploitation de la Mer（IFREMER）, amounts to 1 029 km^3（NSIDC） and1 463 km^3（IFREMER）, respectively. For this period, a mean monthly volume flux（area flux） difference between the estimates derived from the NSIDC and IFREMER drift data is –62 km^3 per month（–18×10~6 km^2 per month）.Analysis reveals that this negative bias is mainly attributable to faster IFREMER drift speeds in comparison with slower NSIDC drift data. NSIDC-based sea ice volume flux estimates are compared with the results from the University of Bremen（UB）, and the two products agree relatively well with a mean monthly bias of（5.7±45.9） km^3 per month for the period from January 2011 to August 2013. IFREMER-based volume flux is also in good agreement with previous results of the 1990 s. Compared with P1（1990/1991–1993/1994） and P2（2003/2004–2007/2008）, the WAVF estimates indicate a decline of more than 600 km^3 in P3（2011/2012–2014/2015）. Over the three periods, the variability and the decline in the sea ice volume flux are mainly attributable to sea ice motion changes, and second to sea ice thickness changes, and the least to sea ice concentration variations.
基金Project supported by the National Key R&D Program of China(Grant Nos.2017YFA0303302 and 2018YFA0305602)the National Natural Science Foundation of China(Grant No.11921005)Shanghai Municipal Science and Technology Major Project,China(Grant No.2019SHZDZX01)。
文摘We present a quantum adiabatic algorithm for a set of quantum 2-satisfiability(Q2SAT)problem,which is a generalization of 2-satisfiability(2SAT)problem.For a Q2SAT problem,we construct the Hamiltonian which is similar to that of a Heisenberg chain.All the solutions of the given Q2SAT problem span the subspace of the degenerate ground states.The Hamiltonian is adiabatically evolved so that the system stays in the degenerate subspace.Our numerical results suggest that the time complexity of our algorithm is O(n^(3.9))for yielding non-trivial solutions for problems with the number of clauses m=dn(n-1)/2(d■0.1).We discuss the advantages of our algorithm over the known quantum and classical algorithms.
