Journal of the Japanese Society of Snow and Ice

Isotopic exchange between snow particles and contained water on wet snow layers

Shigemasa HASHIMOTO, Zhou SHIQIAO, Masayoshi NAKAWO, Akiko SAKAI, Yuta ...

2002 Volume 64 Issue 2 Pages 163-172
Published: March 15, 2002
Released on J-STAGE: February 05, 2010

DOIhttps://doi.org/10.5331/seppyo.64.163

JOURNAL FREE ACCESS

Show abstractHide abstract

Snow pit studied were carried out at Moshiri, Hokkaido, once a day for about a week in April, 1998, while the snow layers were at the melting point. We collected the samples of snow particles and the liquid water in between the particles every 5cm throughout the depth. The precipitation and the runoff water from the bottom of the snow pack were also collected during the observation period. Isotope analysis on oxygen and hydrogen has been made with those samples.
The isotope ratio of snow particles was larger than the water abundant in the snow layers. The difference in isotope ratio between the snow particles and the water was small near the surface and increased with depth. The isotope ratio for snow particles as well as liquid water increased with time. The results indicated that the vertical water flow through the snow layers plays a major role for isotopic change of snow particles.

View full abstract

Download PDF (4768K)
Sulfur Isotope Ratios of Non-Sea Salt Sulfate in Wet Deposits in Japan

Naofumi AKATA, Fumitaka YANAGISAWA, Remi MOTOYAMA, Akiko KAWABATA, Aki ...

2002 Volume 64 Issue 2 Pages 173-184
Published: March 15, 2002
Released on J-STAGE: August 07, 2009

DOIhttps://doi.org/10.5331/seppyo.64.173

JOURNAL FREE ACCESS

Show abstractHide abstract

In Japan, wet deposition is mainly from sulfuric acid rather than nitric acid, and acid rain falls even in non-industrial regions along the Japan Sea coast as well as in industrial regions facing the Pacific Ocean. In order to clarify the sources of non-sea salt sulfate in Japan, sulfur isotope ratios of non-sea salt sulfate in wet deposits were evaluated and sulfur isotope ratios of non-sea salt sulfate in wet deposits were compiled from the literature. At most sites, the isotopic ratios of non-sea salt sulfate observed in the summer were0‰. The sulfur isotope ratios of non-sea salt sulfate showed seasonal variation with an increase in winter. This seasonal variation suggests that non-sea salt sulfate in wet deposits was derived from the source, having a higher sulfur isotope ratio in winter. The sulfur isotope ratios of non-sea salt sulfate collected in Japan in winter were in agreement with the sulfur values for coals in East Asia.
The northwest Siberia monsoon dominates Japan in the winter and the deposition rate of non-sea salt sulfate increases at that time. Sulfur oxides produced by coal combustion in East Asia make a high contribution in winter. Maximum values of sulfur isotope ratios of non-sea salt sulfate in northern Japan are higher than those in southern Japan in winter. This pattern suggests that non-sea salt sulfate in northern Japan was derived from a source having a higher sulfur isotope ratio in winter. The back-trajectory at the 850 hPa level starting at Okushiri Island passed over northeast China, while those at Shimonoseki passed by the Korean Peninsula one or two days before sampling. Sulfur isotope ratios of coals from northern East Asia are higher than those in southern East Asia. It is suggested that in winter, wet deposits in northern Japan contains sulfur released by the combustion of coals in northern East Asia, while that in southern Japan contains sulfur released by the combustion of coals in southern East Asia.

View full abstract

Download PDF (2816K)
Depth hoar as a proxy for the ground temperature transition in winter

Yuki SAWADA, Mamoru ISHIKAWA, Yugo ONO

2002 Volume 64 Issue 2 Pages 185-190
Published: March 15, 2002
Released on J-STAGE: February 05, 2010

DOIhttps://doi.org/10.5331/seppyo.64.185

JOURNAL FREE ACCESS

Show abstractHide abstract

We found a good correlation (R²=0.79) between the BTS (Basal Temperature of Snow) value and thickness of the depth hoar layer in a block slope at Mt. Higashi-nupukaushinupuri (1251 m a.s.l.), central Hokkaido. Temperature gradients of snow were estimated from air temperature and snow depth data in the nearest meteorological station. Maximum temperature gradients appeared in December, when snow cover was thin. This fact suggests that the temperature gradients in December can promote growing of depth hoar layers not only in the high BTS condition, but also where BTS is low. Therefore, depth hoar layer thickness may vay between high and low BTS conditions in January and February, when snow cover reaches a maximum. We conclude that the thickness of the depth hoar layer reflects the difference of the BTS value in winter.

View full abstract

Download PDF (1920K)

Register with J-STAGE for free!