Seasonal variation of moisture transport in polar regions and the relation with annular modes

Climatological seasonal variations of moisture transport and the interannual variations associated with the annular modes in the Arctic and Antarctic regions are investigated using 15-year ECMWF reanalysis data. Over the Arctic, there are strong moisture inflows from the Atlantic and Pacific in all seasons. Over the Antarctic, a strong moisture inflow exists around the Antarctic Peninsula in all seasons and another strong inflow exists over the Bellingshausen Sea and the Amundsen Sea in austral autumn and winter. Transient moisture flux is dominant over stationary flux and transient flux variation mainly controls the seasonal variation of precipitation minus evaporation(P-E) in both regions. The seasonal variations of P-E show a summer maximum in the Arctic and a winter maximum in the Antarctic. It is mainly governed by the seasonal variation of precipitable water variation in the Arctic and transient eddy activity in the Antarctic. The zonal mean poleward and eastward moisture fluxes in high latitudes are positively correlated with annular modes in both regions. Positive polarity of the Arctic Oscillation is associated with enhanced moisture inflow from the Atlantic, while positive polarity of the Antarctic Oscillation is associated with enhanced moisture inflow west of the Antarctic Peninsula

Warming climate-derived changes in terrestrial Arctic evapotranspiration budget and the impact to hydrological cycle

第6回極域科学シンポジウム分野横断セッション：[IA] 急変する北極気候システム及びその全球的な影響の総合的解明―GRENE北極気候変動研究事業研究成果報告2015―11月19日（木）　国立極地研究所１階交流アトリウ

Atmospheric hydrological cycles in the Arctic and Antarctic during the past four decades

Atmospheric hydrological cycles over the Arctic and Antarctic have been investigated in the previous studies and there are some similarity and dissimilarity in the two polar regions. The Arctic and Antarctic are areas of moisture flux convergence through the year. So the precipitation (P) exceeds the evaporation (E) and the net precipitation (P-E) is positive. Therefore, the atmospheric moisture transport is a primary input of water into the polar regions. Meanwhile the climatological seasonal cycles of P-E over these regions are dominated by transient moisture flux associated with cyclone activities, the interannual variations are governed by the stationary flux associated with the Arctic Oscillation and the Antarctic Oscillation (AAO). In addition, recent climate changes influence the polar hydrological cycles. Our analyses using an atmospheric reanalysis up to recent years indicated that there were no significant long-term changes in the poleward moisture transport into both the Arctic and Antarctic during 1979-2016. On the other hand, the water vapor (precipitable water) were clearly increasing over the Arctic and gradually decreasing over the Antarctic during the same period. As expected, the increasing trend of water vapor was due to the large warming over the Arctic. There were two reasons for the gradually decreasing trend of water vapor over the Antarctic. The first one was the positive trend of AAO in summer and the second was deepening trend of the Amundsen low in autumn. The trends in water vapor and temperature during the past 38 years further suggest that both polar regions were getting dryer in several seasons. The trend, however, needs to be confirmed by follow-up climatological analyses

Interannual variation of the Lena River discharge and its association with atmospheric water cycle

第3回極域科学シンポジウム/第35回極域気水圏シンポジウム 11月30日（金） 国立国語研究所 ２階多目的

Quantification of Warming Climate-Induced Changes in Terrestrial Arctic River Ice Thickness and Phenology

A land process model [the coupled hydrological and biogeochemical model (CHANGE)] is used to quantitatively assess changes in the ice phenology, thickness, and volume of terrestrial Arctic rivers from 1979 to 2009. The CHANGE model was coupled with a river routing and discharge model enabling explicit representation of river ice and water temperature dynamics. Model-simulated river ice phenological dates and thickness were generally consistent with in situ river ice data and landscape freeze–thaw (FT) satellite observations. Climate data indicated an increasing trend in winter surface air temperature (SAT) over the pan-Arctic during the study period. Nevertheless, the river ice thickness simulations exhibited a thickening regional trend independent of SAT warming, and associated with less insulation and cooling of underlying river ice by thinning snow cover. Deeper snow depth (SND) combined with SAT warming decreased simulated ice thickness, especially for Siberian rivers, where ice thickness is more strongly correlated with SND than SAT. Overall, the Arctic river ice simulations indicated regional trends toward later fall freezeup, earlier spring breakup, and consequently a longer annual ice-free period. The simulated ice phenological dates were significantly correlated with seasonal SAT warming. It is found that SND is an important factor for winter river ice growth, while ice phenological timing is dominated by seasonal SAT. The mean total Arctic river ice volume simulated from CHANGE was 54.1 km3 based on the annual maximum ice thickness in individual grid cells, while river ice volume for the pan-Arctic rivers decreased by 2.82 km3 (0.5%) over the 1979–2009 record. Arctic river ice is shrinking as a consequence of regional climate warming and coincident with other cryospheric components, including permafrost, glaciers, and sea ice

Megalocytiviruses

The genus Megalocytivirus, represented by red sea bream iridovirus (RSIV), the first identified and one of the best characterized megalocytiviruses, Infectious spleen and kidney necrosis virus (ISKNV), the type species of the genus, and numerous other isolates, is the newest genus within the family Iridoviridae. Viruses within this genus are causative agents of severe disease accompanied by high mortality in multiple species of marine and freshwater fish. To date outbreaks of megalocytivirus-induced disease have occurred primarily in south-east Asia and Japan, but infections have been detected in Australia and North America following the importation of infected ornamental fish. The first outbreak of megalocytiviral disease was recorded in cultured red sea bream (Pagrus major) in Japan in 1990 and was designated red sea bream iridovirus disease (RSIVD). Following infection fish became lethargic and exhibited severe anemia, petechiae of the gills, and enlargement of the spleen. Although RSIV was identified as an iridovirus, sequence analyses of RSIV genes revealed that the virus did not belong to any of the four known genera within the family Iridoviridae. Thus a new, fifth genus was established and designated Megalocytivirus to reflect the characteristic presence of enlarged basophilic cells within infected organs. Indirect immunofluorescence tests employing recently generated monoclonal antibodies and PCR assays are currently used in the rapid diagnosis of RSIVD. For disease control, a formalin-killed vaccine was developed and is now commercially available in Japan for several fish species. Following the identification of RSIV, markedly similar viruses such as infectious spleen and kidney necrosis virus (ISKNV), dwarf gourami iridovirus (DGIV), turbot reddish body iridovirus (TRBIV), Taiwan grouper iridovirus (TGIV), and rock bream iridovirus (RBIV) were isolated in East and Southeast Asia. Phylogenetic analyses of the major capsid protein (MCP) and ATPase genes indicated that although these viruses shared considerable sequence identity, they could be divided into three tentative species, represented by RSIV, ISKNV and TRBIV, respectively. Whole genome analyses have been reported for several of these viruses. Sequence analysis detected a characteristic difference in the genetic composition of megalocytiviruses and other members of the family in reference to the large and small subunits of ribonucleotide reductase (RR-1, RR‑2). Megalocytiviruses contain only the RR-2 gene, which is of eukaryotic origin; whereas the other genera encode both the RR-1 and RR-2 genes which are thought to originate from Rickettsia-like α-proteobacteria

2015年「みらい」北極航海における海洋観測

MR15-03講演要旨 / ブルーアース2016（2016年3月8日～9日, 東京海洋大学品川キャンパス）http://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr15-03/

Influence of the Antarctic sea-ice anomaly upon largescale atmospheric circulation in the Southern Hemisphere by using AGCM

第3回極域科学シンポジウム/第35回極域気水圏シンポジウム 11月30日（金） 国立国語研究所 ２階多目的

Nationwide surveillance of AIDS-defining illnesses among HIV patients in Japan from 1995 to 2017

Objectives: The accurate prevalence of acquired immunodeficiency syndrome (AIDS)-defining illnesses (ADIs) in human immunodeficiency virus (HIV)-infected patients has not been well investigated. Hence, a longitudinal nationwide surveillance study analyzing the current status and national trend of opportunistic complications in HIV-infected patients in Japan is warranted.Methods: A nationwide surveillance of opportunistic complications in HIV-infected patients from 1995 to 2017 in Japan was conducted. An annual questionnaire was sent to 383 HIV/AIDS referral hospitals across Japan to collect information (CD4+ lymphocyte count, time of onset, outcome, and antiretroviral therapy [ART] status) of patients diagnosed with any of 23 ADIs between 1995 and 2017.Results: The response and case capture rates of the questionnaires in 2017 were 53% and 76%, respectively. The number of reported cases of opportunistic complications peaked in 2011 and subsequently declined. Pneumocystis pneumonia (38.7%), cytomegalovirus infection (13.6%), and candidiasis (12.8%) were associated with the cumulative incidence of ADIs between 1995 and 2017. The mortality rate in HIV-infected patients with opportunistic complications substantially decreased to 3.6% in 2017. The mortality rate was significantly higher in HIV patients who received ART within 14 days of diagnosis of complications than in those who received ART 15 days after diagnosis (13.0% vs. 3.2%, p < 0.01).Conclusions: We have demonstrated a 23-year trend of a newly diagnosed AIDS status in Japan with high accuracy. The current data reveal the importance of Pneumocystis pneumonia as a first-onset illness and that early initiation of ART results in poor outcomes in HIV patients in Japan