scholarly journals Ensemble simulations of the influence of regionally warm sea surface on moisture and rainfall in Tsushima Strait during August 2013

2020 ◽  
Vol 238 ◽  
pp. 104876 ◽  
Author(s):  
Masaru Yamamoto
Keyword(s):  
Sea Surface ◽  
Tsushima Strait ◽  
Ensemble Simulations

scholarly journals Effect of western U.S. snow cover on climate

2001 ◽  
Vol 32 ◽  
pp. 82-86 ◽  
Author(s):  
Susan Marshall ◽  
Robert J. Oglesby ◽  
Anne W. Nolin
Keyword(s):  
Snow Cover ◽  
Thermal Effects ◽  
Climate Model ◽  
Regional Climate ◽  
Sea Surface ◽  
System Response ◽  
Initial State ◽  
Climate Anomalies ◽  
Ensemble Simulations ◽  
Sensitivity Studies

AbstractThe purpose of this study is to identify characterize and quantify local, regional and remote effects of snow cover on western U. S. climate and water resources. An ensemble of predictability and sensitivity studies was made with the U.S. National Center for Atmospheric Research (NCAR) Community Climate Model, version 3 (CCM3) to investigate the relative roles of snow-cover anomalies and initial atmospheric states in the subsequent accumulation and ablation seasons. The suite of model experiments focuses on the direct effect of snow on regional climate anomalies and ultimately will be used to examine the lagged effect of anomalous snow cover on the climate. The set of ensemble simulations presented here looks at the climate-system response to anomalously high and low snow cover at the start of the ablation season over the western U.S.A. These current results suggest that the initial state of snow cover is more important than the initial state of the atmosphere or of sea-surface temperatures because of direct thermal effects on the surface and subsequent indirect, dynamical effects on the atmospheric circulation.

scholarly journals Long-term trends of oxygen concentration in the waters in bank and shelves of the Southern Japan Sea

2021 ◽  
Author(s):  
Tsuneo Ono
Keyword(s):  
Water Column ◽  
Japan Sea ◽  
Summer Season ◽  
Sea Surface ◽  
Tsushima Strait ◽  
Continental Shelves ◽  
Japan Sea Proper Water ◽  
Long Term Trends ◽  
Wakasa Bay

AbstractWhile multiple studies have investigated oxygen decrease in Japan Sea Proper Water (JSPW; > 300 m in depth), oxygen variation in continental slope and shelf waters (< 300 m) must also be investigated in order to assess its socioecological impacts. In this study, historical oxygen data in the waters of three continental shelves and a bank of Japan Sea, off-Awashima area (AW), Wakasa Bay (WB), East of Tsushima Straight (ETS), and Yamato Bank (YB), were collected and analyzed to assess temporal variation of oxygen in each region from 1960 to 2000s. Significant decreasing trends of oxygen were detected in the waters below 150 m depth in WB and YB, and below 300 m in AW, in the summer season. In winter, a decreasing trend of oxygen was detected throughout the water column from 300 m to the sea surface in WB and YB. In ETS, a deoxygenation trend was detected throughout the water column from the bottom to the sea surface in the summer season, while no trend was detected in winter. The results suggested that oxygen decreases in AW, WB, and YB were the consequence of the upward propagation of the deoxygenation signal from JSPW, while that of ETS was caused by horizontal propagation of deoxygenation signal from the East China Sea. Assuming that the observed trend will continue in future, it is predicted that part of the water in Tsushima Strait area will reach the general sublethal threshold of oxygen (134 μmol kg−1) by the end of this century.

Influence of regionally warm sea surface on moisture and extreme rainfall in Tsushima Strait during August 2013

2020 ◽  
Author(s):  
Masaru Yamamoto
Keyword(s):  
Water Vapor ◽  
Heavy Rainfall ◽  
Central Area ◽  
Extreme Rainfall ◽  
High Water ◽  
Sea Surface ◽  
Rainy Period ◽  
Tsushima Strait ◽  
Moisture Variation ◽  
Hourly Rainfall

&lt;p&gt;The present study investigates short-term (four-day) atmospheric response to regionally warm sea surface in Tsushima Strait for two periods (a sunny period, 19-22 August 2013 and a rainy period, 23-26 August 2013) using ensemble WRF simulations with initial condition altered in the presence and absence of an extremely warm SST core. In this presentation, the author focuses on the influence of regionally warm sea surface on moisture and extreme rainfall. The moisture response is quite different between the sunny and rainy periods. Ensemble averaged distribution of time-mean moisture variation induced by a regionally warm sea surface is well correlated with the SST increase during the sunny period. However, it is not clearly correlated with the SST increase during the rainy period when vapor fluctuated because of frequent rainfall. The high SST enhanced time-mean precipitation in the central area of the warm SST core. In the ensemble experiment, the warm SSTs do not always enhance hourly rainfall because the water-vapor concentrations are decreased by prior rainfall events in some members. In a simulation that well reproduces heavy rainfall at Izuhara located in Tsushima Strait in the presence of the warm SST core, high SSTs induced extreme precipitation (~50 mm/h) in the morning. Water vapor decreased after the morning heavy rainfall. The decreased moisture led to low precipitation in the afternoon. In contrast, a low-SST experiment with the warm-SST core removed shows that water-vapor concentrations were higher after weaker morning rainfall, compared to the high SST experiment with the warm core. Because of the high water-vapor concentrations, low SST led to greater precipitation in the afternoon. Thus, when responses of hourly precipitation to SST are investigated, we must consider the temporal water-vapor variation associated with prior rainfall event.&lt;/p&gt;

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