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Volume 79 (2017)
- Issue 6 Pages 483-
- Issue 5 Pages 403-
- Issue 4 Pages 319-
- Issue 2 Pages 211-
- Issue 1 Pages 3-
Volume 79, Issue 1
Displaying 1-9 of 9 articles from this issue
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Kazuki NAKAMURA, Tsutomu YAMANOKUCHI, Shigeru AOKI, Koichiro DOI, Kazu ...2017 Volume 79 Issue 1 Pages 3-15
Published: 2017
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSThis paper presents that temporal variations in the flow velocity for Shirase Glacier in Antarctica were studied using synthetic aperture radar (SAR) images obtained by the Japanese Earth Resources Satellite-1 (JERS-1) in 1996-1998, the Advanced Land Observing Satellite (ALOS) in 2007-2010 and the ALOS-2 in 2014-2015. The scenes were analyzed using image correlation. The obtained ice-flow velocity increases rapidly from the upstream region to the coast, but its velocity is roughly constant over a region, 10km long about the grounding line (GL), then gradually tends to increase again downstream from the GL. This trend has continued largely unchanged over the 20 years since 1996, judging from the flow velocity profiles obtained from JERS-1/SAR, ALOS/PALSAR and ALOS-2/PALSAR-2 observations. The flow velocity on the central streamline near the GL is 2.29±0.02〜0.03kma−1(mean of 1996-2015). Between the GL and the point 30km downstream, ice velocities tended to be lower in 2007-2010 or 2014-2015 than in 1996-1998. Upstream from the GL, the velocities were higher in 2007-2010 and 2014-2015 than in 1996-1998, increasingly so with distance upstream, reaching a maximum of approximately 0.57kma−1(differences of mean velocity between 2007 and 2010) and 0.72kma−1(differences of mean velocity between 2014 and 2015) at around 18km upstream from the GL before decreasing again to a respective value of〜0.25 and〜0.35kma−1 at 30km upstream.View full abstractDownload PDF (2623K) -
Nuerasimuguli ALIMASI, Hiroyuki ENOMOTO2017 Volume 79 Issue 1 Pages 17-30
Published: 2017
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSCryospheric change due to accelerated warming in the Arctic is a major concern. Such a change influences the environment, resulting in atmospheric, oceanic, and terrestrial changes. Arctic research projects are sending field research groups and establishing observation sites at various places in this region. Satellite observations are available to support research planning, and evaluation of observation period and place, as these observations cover both time and space. The present study used satellite passive microwave observations as they are available even for polar nights when sunlight is not available and also for cloudy or foggy conditions. Microwave data were collected from research sites in North America, Siberia, Svalbard, Scandinavia, and Greenland, where Japanese research groups are visiting. The data were sampled by pixels based on the location data of observation sites and were used for monitoring local snow cover and melting durations. Continental scale migration patterns of snow melting show south‒north and west‒east trends. The snow melting area migrates from south‒west to north‒east at the high latitudes in North America and then reaches Greenland and Svalbard. The snow melting area in the Eurasian Continent was observed to move from west to east, namely Scandinavia to north-east of Siberia, in a shorter period.View full abstractDownload PDF (5742K) -
Kazuhiro NAOKI, Kohei CHO, Shuki USHIO2017 Volume 79 Issue 1 Pages 31-42
Published: 2017
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSThe changing of sea ice in the Arctic and Antarctic has been monitored by satellite on board microwave radiometry since 1978. Understanding the variability of the sea ice brightness temperature is important for accurately estimating the sea ice concentration. Summer sea ice is wet due to the effects of air temperature and solar radiation. Melting water causes drastic changes to the brightness temperature. The purpose of this study is to clarify the brightness temperature variability of multi-year ice during the melting season. We observed multi-year ice offshore at Syowa Station, Antarctica. The brightness temperature was measured from the snow surface, snow pack, and multi-year ice surface. The measurements show that the brightness temperature from the multi-year ice surface had great variability depending on the different surface conditions. However, the brightness temperature from the snow pack remained constant due to the influence of wet snow. For this reason, microwave radiation below the wet snow cannot be transmitted to the upper layer. The brightness temperature of the snow surface is high when the surface is covered by wet snow. By contrast, when the surface is covered by dry snow, the brightness temperature of the snow surface is different depending on the optical thickness of the dry snow. When wet snow is included in the snow pack on multi-year ice, the brightness temperature during the melting season depends on whether the snow surface is dry snow or wet snow.View full abstractDownload PDF (2126K) -
Hiroto NAGAI, Takeo TADONO2017 Volume 79 Issue 1 Pages 43-61
Published: 2017
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESS -
Daiki SAKAKIBARA2017 Volume 79 Issue 1 Pages 63-71
Published: 2017
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESS -
Kazuki NAKAMURA, Toshifumi MORIYAMA, Kohei OSA2017 Volume 79 Issue 1 Pages 73-81
Published: 2017
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESS -
Yoshitaka KAWADA2017 Volume 79 Issue 1 Pages 89-104
Published: 2017
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSThis study focuses on a water circulating-type snow cooling system in which water flows through the bottom layer of the snow. The characteristics of heat exchange between the snow and water were investigated experimentally under the following three different snow storage conditions; 1) laboratory-sized snow stored in a 0℃ room for 0 to 15 days, 2) snow stored in a 12-ton reefer container for about 4 months, 3) snow stored in an 150-ton storage in the actually operated snow cooling facility for about 4 months. The surface shape of the snow and inlet/outlet water temperatures of the heat exchange section were measured at proper time intervals. Regarding the change in shape of the snow, phenomena such that there was almost no change during a certain period, the open crack occurred in the snow and the snow lump suddenly subducted were observed. The outlet water temperature varied according to the phenomena. How the crack occurred differed somewhat according to the snow storage conditions. The heat exchange performance between the snow and water decreased with the snow storage periods. The decrease clearly appeared even in 1 day. The ratio of the water temperature drop due to heat exchange with the snow to the temperature difference between the pump-feeding water and the snow varied with the water-flowing direction length of the snow at the initial and a given time, the gap length between the snow and the side wall, and the snow storage period.View full abstractDownload PDF (3782K) -
Hiroshi GOTO, Masahiro KAJIKAWA, Hiroji TAKAHASHI, Hirotake TAKAHASHI, ...2017 Volume 79 Issue 1 Pages 105-116
Published: 2017
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSTo investigate the relationship between the variation in the size of perennial snow patches and climatic elements, a periodical survey of the Southeastern Nanatsugama snow patch located on the northeastern slope of Mt. Chokai (39° 06N, 140° 03E, 2236m in altitude) was conducted during the ablation seasons of 1980-2014. The main results are summarized as follows： 1）The long-range trend in the size of snow patches is not statistically significant, except for the annual variation. 2）Climatic conditions influence the size of snow patches in the first stage (until August) of the ablation season, exhibited by the following statistically significant climatic elements (significance level of 5%): precipitation and air temperature at the foot of Mt. Chokai, observed during the accumulation season (from the previous November to March) at the Yashima meteorological station; wind speed and height at the 850-hPa isobaric surface, observed during the accumulation season at the Akita meteorological observatory. 3）Climatic conditions influence the ablation of snow patches, exhibited by the following statistically significant climatic elements (significance level of 5%): accumulated sunshine duration and accumulated temperature during the ablation season (from August to October), observed at the Yashima station.View full abstractDownload PDF (3028K) -
Minami YASUI2017 Volume 79 Issue 1 Pages 117-132
Published: 2017
Released on J-STAGE: March 02, 2023
JOURNAL OPEN ACCESS
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