The Okhotsk tropospheric cyclone and its role in the occurrence of extreme air temperature in January in 1950-2019

2021 ◽  
Vol 3 ◽  
pp. 64-79
Author(s):  
T.A. Shatilina ◽  
◽  
G.Sh. Tsitsiashvili ◽  
T.V. Radchenkova ◽  
◽  
...  
Keyword(s):  
Air Temperature ◽  
Geopotential Height ◽  
Sea Of Okhotsk ◽  
Small Neighborhood ◽  
Surface Air Temperature ◽  
Major Axis ◽  
Eastern Coast ◽  
Study Region ◽  
Extreme Surface ◽  
The Sea Of Okhotsk

The field of Н500 geopotential height over the central part of the second natural synoptic region in January during 1950–2019 is analysed to determine regime characteristics of the Okhotsk tropospheric cyclone and its role in the formation of air temperature anomalies over the eastern coast of Asia. A mechanism of occurrence of extreme surface air temperatures using this technique is presented. Extremely low air temperature in the area of the minimum and related deep through are formed during the years when the Н500 minimum is localized over the Sea of Okhotsk. A methodology for constructing ellipses approximating the Н500 level lines in a small neighborhood of the Н500 minimum is developed, the ellipse characteristics are calculated, and their relation to the tropospheric cyclone evolution is analysed. The characteristics of the ellipses constructed in the neighborhood of the geopotential height minimum outside the Sea of Okhotsk significantly differ from those of the ellipses over the Sea of Okhotsk. A high compression of the ellipses towards the major axis is reported when the Far Eastern through intensity is reduced. In this case, an outflow of warm oceanic air masses to the Sea of Okhotsk is observed. The location of the Н500 minimum and the characteristics of the ellipses located within the center circle may be used to explain reasons for dramatic changes in air temperature in the study region. Keywords: Оkhotsk tropospheric cyclone, Н500 minima centers, extreme surface air temperature, ellipse characteristics

scholarly journals Sensitivity of Precipitation Phase over the Swiss Alps to Different Meteorological Variables

2014 ◽  
Vol 15 (2) ◽  
pp. 685-696 ◽  
Author(s):  
S. Froidurot ◽  
I. Zin ◽  
B. Hingray ◽  
A. Gautheron
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Meteorological Data ◽  
Explanatory Power ◽  
Surface Air Temperature ◽  
Ground Level ◽  
Swiss Alps ◽  
Meteorological Variables ◽  
Study Region ◽  
Precipitation Phase

Abstract In most meteorological or hydrological models, the distinction between snow and rain is based only on a given air temperature. However, other factors such as air moisture can be used to better distinguish between the two phases. In this study, a number of models using different combinations of meteorological variables are tested to determine their pertinence for the discrimination of precipitation phases. Spatial robustness is also evaluated. Thirty years (1981–2010) of Swiss meteorological data are used, consisting of radio soundings from Payerne as well as present weather observations and surface measurements (mean hourly surface air temperature, mean hourly relative humidity, and hourly precipitation) from 14 stations, including Payerne. It appeared that, unlike surface variables, variables derived from the atmospheric profiles (e.g., the vertical temperature gradient) hardly improve the discrimination of precipitation phase at ground level. Among all tested variables, surface air temperature and relative humidity show the greatest explanatory power. The statistical model using these two variables and calibrated for the case study region provides good spatial robustness over the region. Its parameters appear to confirm those defined in the model presented by Koistinen and Saltikoff.

Ice Season forecast under ClimateChange: Tipping element approach

2020 ◽  
Author(s):  
Elena Surovyatkina ◽  
Roman Medvedev
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Sea Of Okhotsk ◽  
Surface Air Temperature ◽  
Critical Threshold ◽  
Data Set ◽  
Near Surface ◽  
The Sea Of Okhotsk ◽  
Starting Point ◽  
Element Approach

<p>The Sea of Okhotsk is a marginal sea of the western Pacific Ocean. It is one of the world's richest in biological resources and famous for the fishing industry. In winter, navigation on the Sea is difficult, if not impossible, due to the harsh conditions of the North and the presence of sea ice. On average, the ice-free period lasts from June to November. However, the start and end dates of the ice season vary from year to year within a month. Such variability is impossible to capture by meteorological methods, which have a limit of predictability for 10 days. The absence of a long-term forecast of the navigational period in the Sea of Okhotsk affects the safety of navigation and the reliability of transit transport.</p><p>Most of the studies of the distribution of ice floes focus on such factors as the location, time of year, water currents, and sea temperatures. In our study, we use the distribution of temperature in the atmosphere and wind direction (NCEP/NCAR re-analyses data set) because most of the area of the Sea of Okhotsk is located in monsoon climate zone. We propose a new approach to forecast predicting the upcoming ice advance/ retreat date by developing our Tipping element approach [1] elaborated for prediction of the Indian Summer Monsoon, which proved to be successful for prediction upcoming monsoon four years in a row (2016-2019).</p><p>The physical mechanism underlying forecast is the following. There is an atmospheric feature that appears at the beginning of the transition to the ice season. We show, for the first time, the evidence in observational data that a transition from open water season to ice season begins when the near-surface air temperature crosses a critical threshold. It appears in the form of spatially organized critical transitions in the atmosphere over the see. This event happening 2-3 months before the ice season is a starting point forecasting date of ice advance. We perform forecast in critical areas - tipping elements of the spatial structure of ice formation, which we identified via data analysis.</p><p>The retrospective test (over the period 2001-2017) confirms that the methodology allows forecasting the ice advance/retreat date more than one month in advance, with a success rate in 88% of the years within the error of +/- 4 days. Forecasts of the upcoming season 2018-2019 show successful results as well.</p><p>Climate change affects the ice season in the Sea of Okhotsk in the following aspects: there has been a declining trend in sea ice cover in recent years due to delays in the ice advance date. Season shift because it takes for the atmosphere longer time cooling down in autumn. The novel approach allows for accounting climate change effects.</p><p>ES acknowledges financial support of the EPICC project (18_II_149_Global_A_Risikovorhersage) funded by BMU, RM acknowledges the Russian Foundation for Basic Research (RFBR) (No. 20-07-01071)</p><p>[1] Stolbova, V., E. Surovyatkina, B. Bookhagen, and J. Kurths (2016): Tipping elements of the Indian monsoon: Prediction of onset and withdrawal. GRL 43, 1–9 [doi:10.1002/2016GL068392]</p>

Contribution to the flora of marine algae of the coastal zone of the northeastern part of the Sea of Okhotsk

2018 ◽  
Vol 52 (1) ◽  
pp. 63-73
Author(s):  
N. V. Evseeva
Keyword(s):  
Coastal Zone ◽  
Sea Of Okhotsk ◽  
Marine Algae ◽  
Herbarium Material ◽  
Northeastern Part ◽  
The Sea Of Okhotsk ◽  
The Family ◽  
First Time

The revision of the herbarium material, collected in the northern part of the Sea of Okhotsk in 1965–1966 and stored in VNIRO, allowed to expand the taxonomic list of macrophyte algae of the coastal zone of this area. The locations of discovery of 24 previously unmentioned species are described. Myrionema balticum, Ulvella repens, Syncoryne reinkei, Acrochaetium arcuatum were found in the Sea of Okhotsk for the first time. Most species new for the Sea of Okhotsk is represented by epiphytes of the family Ulvellaceae (Chlorophyta). The final taxonomic list of this region, including literature data, consists of 169 species.

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