First Record of the Pallas's Warbler Phylloscopus proregulus in the Northern Japan

Late Neogene Radiolarian Biostratigraphy in the Subarctic Northwest Pacific

Eolian dust from the lower atmosphere of the eastern Atlantic and Indian Oceans, China Sea and Sea of Japan

The Sea of Okhotsk, between northern Japan and Siberia, is the southernmost sea region of the Northern Hemisphere with seasonal sea ice cover. During early spring, occasional rapid reduction in sea ice cover observed in the southern Sea of Okhotsk can lead to anomalously early disappearance of sea ice along the Hokkaido coast (northern Japan). This study investigated the atmospheric and oceanic processes leading to rapid reduction in sea ice in the southern Sea of Okhotsk during early spring. We detected six events of subseasonal continued reduction in sea ice cover in March between 1993 and 2019. Strong southerly winds with marked thermal advection and moisture transport over northern Japan were observed in five of the six events. The passage of extratropical cyclones brought warm moist air from the south, which led to drifting and melting of sea ice by changing the surface wind speed and surface heat budget in the southern Sea of Okhotsk. The perturbation in sensible heat flux attributable to warm air advection contributed substantially to sea ice reduction, whereas longwave radiation played a secondary role. In addition to the atmospheric processes, an enhanced Soya Current also transports heat from the Sea of Japan, possibly contributing to the sea ice melt. The initial sea ice reduction leads to further sea ice loss through ice–albedo feedback, resulting in prolonged sea ice reductions for 1–2 weeks.

The <scp>UK</scp>’s wet and stormy winter of 2013/2014

We analyzed patterns of genetic diversity in the sailfin sandfish (Arctoscopus japonicus), focusing on population subdivisions within the Sea of Japan. We observed 270 specimens from nine sampling sites in 1999–2000, i.e., seven sites in the Sea of Japan and two sites from the Pacific coast of Hokkaido. An additional site (30 specimens) was sampled from eastern Korea in the spawning season of 2004 for comparison. Forty haplotypes, compiled into three haplogroups (A–C), were detected based on the comparison of a 400-bp sequence of the anterior part of the mitochondrial control region. In accordance with previous hypotheses from morphological and molecular analyses, genetic discontinuity between the Sea of Japan and the Pacific coast of Hokkaido was conspicuous. Within the Sea of Japan, eight sampling sites were not genetically uniform, and most of the variations among sites were detected between eastern Korea [the “eastern Korea” (EK) population: distributed from the Korean Peninsula to Mishima, Yamaguchi Prefecture] and the other sites along the coast of Japan [the “western Japan” (WJ) population: from Oki Islands to western Hokkaido] (Φ CT = 0.096, P = 0.0183). The WJ population, having lower genetic variability, showed significant departure from neutrality, indicating influences through a recent population expansion. The period of the expansion can be estimated to have begun on the order of 104 years ago. We consider that the present Japan Sea populations have been formed through the invasion of a small ancestral stock to the Sea of Japan and its population expansion during the last glacial period or later. On the other hand, we failed to detect distinct evidence of a population expansion in the EK population. Haplogroup C, detected in a high frequency in this population, was estimated to have mixed with haplogroup A after rapid differentiations of the latter. Therefore, the EK population, strongly influenced by such a mixture, might possess haplogroup C in a higher frequency and a different haplotype composition from the WJ population.

ABSTRACTBlack Storks Ciconia nigra breeding in Europe use two main migratory routes to winter in Africa: a western route over Gibraltar and an eastern route through Turkey and Israel. A broad area of migratory divide exists in central Europe. We examined cases from the Czech Republic wherein siblings from one nest used different migration routes. We found 20 such cases associated with 18 nests distributed throughout the entire territory of the Czech Republic. Moreover, one bird hatched in 2007 used the western migration route in 2007 and the eastern one in 2009. The actual geographical position of a juvenile Black Stork from an area of migratory divide in the autumn period of migratory restlessness (after the dispersal period) influences the decision to choose the western or eastern direction of migration. We also propose that Black Storks that are older than one year and therefore with experience of past migrations could decide their direction of autumn migration and be followed by inexperienced juvenile Black Storks. Siblings originating from an area of migratory divide can commonly use both main migration routes.

Detailed observational study and numerical prediction experiment are made on the extremely strong dry wind event over the northeastern Japan in 27 April 1983, which causedbig forest fires of -9000ha.This extremely strong dry wind took place under the synoptic situation of strong pressure gradient between an extratropical cyclone over the Japan Sea and an anticyclone over the Pacific. The observational study reveals that the abrupt increase of SW-WSW wind with the decrease of relative humidity and temperature rise took place around noon over the lee-side of mountains. The distinct low-level inversion layer observed at 09LST 27 over Sendai (the Pacific coast of the northeastern Japan) was not observed at 21LST 27.The thick dry neutral layer observed at 21LST indicates that the inversion layer was destroyed by convective motions generated over the ground heated by insolation. At the peak period (15LST) of the strong wind, the wind speed at the surface reached to that at 900mb. These observed features suggest that the convective mixing of the momentum is one of the important factors to cause the strong surface wind in 27 April 1983. The prediction experiment of this strong wind event was made by using a 16-layer 64 km-mesh primitive equation model which includes parameterization schemes of various boundary layer physical processes. While a model including both diurnal variation of insolation and mountains (S-M model) simulates the strong dry wind event fairly accurately, a model including only the diurnal variation of insolation (S model) does not simulate. The analysis of the predicted result indicates that the orographically induced downward motion in the S-M model suppresses the formation of cloud against the thermally generated convection and maintains the strong radiative heating and concomitant convective mixing throughout the afternoon. This prediction experiment demonstrates that even the localized strong wind event can be predicted by the high resolution primitive equation model.

The Japanese Pacific stock (JPS) and the northern Japan Sea stock (JSS) of walleye pollock Theragra chalcogramma are mainly distributed in the Pacific Ocean and the Sea of Japan off northern Japan, respectively. This paper summarizes and compares the factors affecting the recruitment variability of these two stocks. Spawning season is from December to March for both stocks. JPS recruitment has a positive relationship with the water temperature in January and February, whereas that of JSS has a negative relationship with the water temperature in January, February, and April. One possible reason for this is that pollock larvae have an optimum growth temperature of approximately 5 °C in the field. Drift of early life stages also appears to be an important influence on the recruitment of both stocks. Because the current generated by the northwest wind carries eggs of JPS into the main larval nursery ground, JPS recruitment is enhanced in years when the northwest wind is predominant in February. On the other hand, early life stages of JSS are transported into the nursery ground by the Tsushima Warm Current. However, this current also carries early life stages into the Sea of Okhotsk and offshore, resulting in poor JSS recruitment in years when this current is strong in March. In contrast to JPS, the recruitment of which is significantly impacted by cannibalism, young pollock have not been found in the stomachs of adult JSS. Warm temperatures in the Sea of Japan seem to induce the separation of young and adult pollock, and the shape of the stock–recruitment relationship also suggests that cannibalism is not important for JSS. Based on this knowledge, and on the hatch date distributions of larvae and juveniles, we propose mechanisms that can explain the recruitment fluctuations for JPS and JSS pollock.

The interannual variation in cold-air outbreak activity over the Japan Sea is investigated using Japan Meteorological Agency buoy 21002 and Quick Scatterometer (QuikSCAT) wind data, Japan Oceanographic Data Center sea surface temperature (SST) data, NCEP–NCAR reanalysis surface wind and sea level pressure (SLP) data, and the winter Arctic Oscillation (AO) index of Thompson and Wallace. Cold-air outbreaks occur during the “winter” November–March period, and wind data for this season for the 19-winter period 1981–2000 were analyzed. Wavelet spectra averaged between 5- and 15-day periods were used to evaluate the intensity of cold-air outbreaks quantitatively. The winter mean wavelet spectra exhibited a clear interannual variation and a significant positive correlation with the AO index, indicating that intensive cold-air outbreaks frequently occur during relatively warm winters caused by a quasi-decadal AO. Based on the SST and SLP data, the low atmospheric surface pressure disturbances tend to develop over the warm East China Sea in warm winters in the positive AO phase. As these low SLP disturbances advance toward the northern Japan islands during the positive AO phase, they intensify more, leading to stronger cold-air outbreaks over the Japan Sea and increased sea surface cooling over the northern Japan Sea.

In the twenty-first century, there was a sharp increase in migration from sub-Saharan Africa to Algeria, and the Sahel zone became a hot stop for illegal human smuggling. Some immigrants go to the north of the country to continue their journey to Europe; others remain in Algeria, treating it as a destination country and do not continue their journey. Algeria has been repeatedly accused of using illegal practices against migrants, such as deportations, pushbacks, and detentions. The aim of the article is to try to assess the scale of the problem of illegal immigration in Algeria based on available statistical data and their periodisation. The main routes taken by migrants will be described, as well as the basic principles of migration policy in Algeria. The following hypotheses were put forward: 1) Algeria is mainly a transit country for migrants from sub-Saharan Africa; 2) The main irregular migration routes lead from the Sahel zone; 3) There is unequal treatment of people in terms of violations of Algerian law (division into Algerians and others). For the purposes of the article, the following research methods were used – analysis and synthesis, comparative method, statistical method, and systemic approach.

Application of a hydrodynamic model to long-term monitoring data: exploring transport pathways to identify the source of high toxicity populations of Dinophysis fortii in aquaculture sites in northern Japan.

Vitis vinifera subsp. silvestris, the wild subspecies of Vitis vinifera L., is a unique and valuable genetic resource for cultivated grapevines. At present, this wild form is rare and is spread from the Southern Atlantic coast of Europe to the Western Himalayas. In the present study, six nuclear microsatellite DNAs were analysed in 301 wild grape samples, using factorial correspondence analysis and the Bayesian model. The aim was to detect the distribution of genetic variability and admixture proportions and thus to identify the main routes of recolonization after the quaternary glaciation, as well as signals of secondary contacts in Europe. The results obtained show that some Caucasus and Italian areas played key roles as refugial areas. Moreover, the data suggest the existence of two main migration routes through central Europe during the post-glacial or the inter-glacial periods. The first started from Southern Italy and moved northward, whereas the second originated from refugia possibly located in eastern areas and migrated westwards. This scenario is most likely associated with the population expansion that followed the European Quaternary glaciations. In accordance with this assumption, central Europe is proposed as an admixture confluence of migration routes radiating from separate grapevine refugia

Aeolian dust has a significant environmental impact on the ocean biogeochemical cycles in different timescales. However, spatial and temporal variations of dust transported on long distances in the upper troposphere by the westerly jet, in particular over orbital-millennial timescales, have not been resolved yet. In this study, we present the evidence for changes in the main axis and path of westerly jet over East Asia at millennial-orbital scale during the last glacial period (~60 ka). We examine the grain size characteristics of sediment core LV53-23 collected from the central Japan (East) Sea, which lies the downwind of westerly jet to discuss the evolution of westerly jet since the last glacial period. Our results show that core sediments are composed mainly of silt characterized of eolian dust, which is consistent with those sediment cores discussed in previous studies from the Japan Sea. The median grain-size of silt fraction has similar pattern with environmentally sensitive grain size extracted by standard deviation/grain-size method. The median grain size in silt fraction increased in stadial periods and decreased in interstadial periods, which might be related to changes in the path of westerly jet. During the stadial, the westerly jet mostly located in the the south of the Tibetan Plateau. It can influence the northern part of the Tibetan Plateau extending to 50°N with high speed, which is prerequisite of dust raised to westerlies in northern China and thus carried the coarser dust from nearby Mongolian Gobi and northeastern China to the Japan Sea. During the interstadial, the provenance of the finer aeolian dust was from Taklimakan Desert when westerly jet migrated northward and concentrated within a narrow band at northern Tibetan Plateau with a longer duration. We found the multi-millennial time scales variations during DOI 8, 12, 14, 16 in cores LV53-23 and MD01-2407 located in the southwestern Japan Sea based on the results of NGRIP and GISP 2 Greenland ice cores. Contrasting with grain size variations of the loess-paleosol records (e.g., Gulang Loess sequence), the lowest grain size during the Last Glacial Maximum confirm that the silt fraction of Japan Sea sediment was mostly transported by westerlies instead of East Asian Winter Monsoon. The mechanism driving the orbital scale variability in grain size of aeolian dust in the Japan Sea is mainly forced by variations of ice volume due to summer insolation in the Northern Hemisphere. A southward migration in the main axis of westerly jet and its influential area was affected by a decrease of summer insolation and increase of ice volume in Northern Hemisphere. During the Last Glacial Maximum, although the cold surges and dust storms were intensive, the southward path of westerly jet may decreased the dust entrainment ability transported by westerlies so that downwind received finer grain size eolian dust. This argument is consistent with findings showing that the location of subarctic front in North Pacific during the Last Glacial Maximum was caused by a southward shift of the path of Kuroshio Current which is controlled by westerly jet. During the glacial period, the decreasing grain size of dust in northern site is explained by weaker westerlies in higher latitudes (40°–50°N) caused by the southward shift of westerly jet main axis, while the increase grain size in the southern site is controlled by the increasing of dust transport path because of westerlies speed in lower latitudes.

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 62:71-78 (2014) - DOI: https://doi.org/10.3354/cr01260 Summertime wave height variability along the Pacific and Okhotsk Sea coasts of northern Japan Teruhisa Shimada* Graduate School of Science, Tohoku University, Aramaki Aza Aoba 6-3, Aoba-ku, Sendai, Miyagi 980-8578, Japan *Corresponding author: shimada@ocean.caos.tohoku.ac.jp ABSTRACT: Wave height variability along the Pacific and Okhotsk Sea coasts of northern Japan in June–August is investigated using in situ measurements and reanalysis data. The coastal wave height is dominated by the persistent easterly winds induced by the developed Okhotsk high. These winds, which can induce cool summers in northern Japan, favor wave development toward the coast of northern Japan. The wave variability is enhanced along the coast of northern Tohoku by the strong local winds occurring in the lee of Cape Erimo. The results for variability of wave height along the Pacific and Okhotsk Sea coasts of northern Japan are supported by composite analysis of reanalysis wave data. When the Okhotsk high develops and the resulting easterly winds are dominant, the wave height increases near the coast of and to the east of northern Japan. Wave height also increases in the Japan Sea and along the southern coast of Japan, whereas wave height decreases in the Okhotsk Sea. These wave height variations reflect the distinct wind fields associated with the developed Okhotsk high. Trends in wave height are examined using the in situ measurements available for over 20 yr. Only the decreasing trends in the south of northern Japan in August are statistically significant. KEY WORDS: Wave climate · Okhotsk high · Northern Japan · Significant wave height · Cool summer · Yamase Full text in pdf format PreviousCite this article as: Shimada T (2014) Summertime wave height variability along the Pacific and Okhotsk Sea coasts of northern Japan. Clim Res 62:71-78. https://doi.org/10.3354/cr01260 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 62, No. 1. Online publication date: December 02, 2014 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2014 Inter-Research.

A strong wind event under clear‐air conditions during the 2018 Winter Olympic and Paralympic games in Pyeongchang, Korea, was examined using various datasets. High spatiotemporal resolution wind information was obtained by Doppler lidars, automatic weather stations, wind profiler, sounding observations, reanalysis datasets under the International Collaborative Experiments for Pyeongchang 2018 Olympic and Paralympic winter games (ICE‐POP 2018). This study aimed to understand the possible mechanisms of localized strong winds across a high mountainous area and on the leeside associated with the underlying large‐scale pattern of a low‐pressure system (LPS). The evolution of surface winds shows quite different patterns, exhibiting intensification of strong winds in the leeside and periodically persistent strong winds in upstream mountainous areas with the approaching LPS. The surface wind speed was intensified from ∼3 to ∼12 m s−1 (gusts were stronger than 20 m s−1 above the ground) at a surface station in the leeside. A budget analysis of the horizontal momentum equation suggested that the pressure gradient force (PGF) contributed from adiabatic warming and the passage of LPS was the main factor in the acceleration of the surface wind in the leeward side of the mountains. The detailed 3D winds revealed that the PGF also modulated the background winds at the mountainous station, which caused persistent strong and periodic winds (range of ∼7 to ∼12 m s−1) related to the channeling effect. The evidence showed that under the same synoptic condition of a LPS, different mechanisms are important for strong winds in determining the strength and persistence of orographic‐induced strong winds under clear‐air conditions.