scholarly journals Contribution of winter upwelling in the Gulf of Finland to lake-effect snow in Estonia

Baltica ◽  
2021 ◽  
pp. 137-147
Author(s):  
Ülo Suursaar ◽  
Helve Meitern
Keyword(s):  
Surface Temperature ◽  
Temperature Difference ◽  
Sea Surface ◽  
Gulf Of Finland ◽  
Air Mass ◽  
The North ◽  
Upwelled Water ◽  
Lake Effect ◽  
Temperature Records ◽  
The Gulf Of Finland

The aim of the study was to analyse the sequence of winter (“warm”) upwelling and lake-effect snow (LES) events that deposited up to 50 cm of snow along the North Estonian coast in January–February 2021. Based on weather and aerological data, four episodes of LES were documented. Heavy, localized lake-effect enhanced precipitation occurred along a 30–50 km wide coastal strip bordering the Gulf of Finland when a cold air mass from the north advected over the warmer, unfrozen sea surface. A temperature difference of up to 20°C was revealed between the air mass temperatures measured at the 850 hPa level and at the sea surface. The LES events, in turn, were preceded by upwelling in the southern Gulf of Finland, which was generated by persisting easterly winds. Even when occasionally interrupted by a wind change, the upwelled water still kept sea surface temperature (SST) in the southern half of the Gulf higher, as documented by the water temperature records from the coastal stations of Estonia, SST and salinity imagery retrieved from the SatBaltyk system, and sea ice distribution charts. Differently from summer (cold) upwelling, winter upwelling brought up warmer (2–4°C) water from the sub-surface layers replacing the already cooled down (0–1°C) surface water. Thus, winter upwelling enhanced LES in two ways. Firstly, by not letting the Gulf freeze over, and therefore by providing a fetch. And secondly, by increasing the SST (and therefore also the 850 hPa level – surface temperature difference) by up to 4°C.

scholarly journals Holocene trends in the foraminifer record from the Norwegian Sea and the North Atlantic Ocean

2009 ◽  
Vol 5 (4) ◽  
pp. 2081-2113 ◽  
Author(s):  
C. Andersson ◽  
F. S. R. Pausata ◽  
E. Jansen ◽  
B. Risebrobakken ◽  
R. J. Telford
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Sea Surface ◽  
Norwegian Sea ◽  
The North ◽  
Temperature Reconstructions ◽  
The North Atlantic ◽  
Temperature Records

Abstract. The early to mid-Holocene thermal optimum is a well-known feature in a wide variety of paleoclimate archives from the Northern Hemisphere. Reconstructed summer temperature anomalies from across northern Europe show a clear maximum around 6 ka. For the marine realm, Holocene trends in sea-surface temperature reconstructions for the North Atlantic and Norwegian Sea do not exhibit a consistent pattern of early to mid-Holocene warmth. Sea-surface temperature records based on alkenones and diatoms generally show the existence of a warm early to mid-Holocene optimum. In contrast, several foraminifer and radiolarian based temperature records from the North Atlantic and Norwegian Sea show a cool mid-Holocene anomaly and a trend towards warmer temperatures in the late Holocene. In this paper, we revisit the foraminifer record from the Vøring Plateau in the Norwegian Sea. We also compare this record with published foraminifer based temperature reconstructions from the North Atlantic and with modelled (CCSM3) upper ocean temperatures. Model results indicate that while the seasonal summer warming of the sea-surface was stronger during the mid-Holocene, sub-surface depths experienced a cooling. This hydrographic setting can explain the discrepancies between the Holocene trends exhibited by phytoplankton and zooplankton based temperature proxy records.

scholarly journals Holocene trends in the foraminifer record from the Norwegian Sea and the North Atlantic Ocean

2010 ◽  
Vol 6 (2) ◽  
pp. 179-193 ◽  
Author(s):  
C. Andersson ◽  
F. S. R. Pausata ◽  
E. Jansen ◽  
B. Risebrobakken ◽  
R. J. Telford
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Sea Surface ◽  
Norwegian Sea ◽  
The North ◽  
Temperature Reconstructions ◽  
The North Atlantic ◽  
Temperature Records

Abstract. The early to mid-Holocene thermal optimum is a well-known feature in a wide variety of paleoclimate archives from the Northern Hemisphere. Reconstructed summer temperature anomalies from across northern Europe show a clear maximum around 6000 years before present (6 ka). For the marine realm, Holocene trends in sea-surface temperature reconstructions for the North Atlantic and Norwegian Sea do not exhibit a consistent pattern of early to mid-Holocene warmth. Sea-surface temperature records based on alkenones and diatoms generally show the existence of a warm early to mid-Holocene optimum. In contrast, several foraminifer and radiolarian based temperature records from the North Atlantic and Norwegian Sea show a cool mid-Holocene anomaly and a trend towards warmer temperatures in the late Holocene. In this paper, we revisit the foraminifer record from the Vøring Plateau in the Norwegian Sea. We also compare this record with published foraminifer based temperature reconstructions from the North Atlantic and with modelled (CCSM3) upper ocean temperatures. Model results indicate that while the seasonal summer warming of the sea-surface was stronger during the mid-Holocene, sub-surface depths experienced a cooling. This hydrographic setting can explain the discrepancies between the Holocene trends exhibited by phytoplankton and zooplankton based temperature proxy records.

The Behavior of the Bulk – Skin Sea Surface Temperature Difference under Varying Wind Speed and Heat Flux

1996 ◽  
Vol 26 (10) ◽  
pp. 1969-1988 ◽  
Author(s):  
Gary A. Wick ◽  
William J. Emery ◽  
Lakshmi H. Kantha ◽  
Peter Schlüssel
Keyword(s):  
Heat Flux ◽  
Wind Speed ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Temperature Difference ◽  
Sea Surface

scholarly journals Sea-surface temperature records of Termination 1 in the Gulf of California: Challenges for seasonal and interannual analogues of tropical Pacific climate change

2012 ◽  
Vol 27 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Erin L. McClymont ◽  
Raja S. Ganeshram ◽  
Laetitia E. Pichevin ◽  
Helen M. Talbot ◽  
Bart E. van Dongen ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Gulf Of California ◽  
Tropical Pacific ◽  
Sea Surface ◽  
Temperature Records

Interannual sea surface chlorophyll-a signature in the tropical Atlantic

2021 ◽  
Author(s):  
Fanny Chenillat ◽  
Julien Jouanno ◽  
Serena Illig ◽  
Founi Mesmin Awo ◽  
Gaël Alory ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface ◽  
Tropical Atlantic ◽  
Cold Tongue ◽  
Equatorial Atlantic ◽  
Atlantic Region ◽  
The North ◽  
Sst Anomaly ◽  
Equatorial Band ◽  
North Tropical Atlantic

<div><span>Surface chlorophyll-<em>a </em>concentration (CHL-<em>a</em>) remotely observed by satellite shows a marked seasonal and interannual variability in the Tropical Atlantic, with potential consequences on the marine trophic web. Seasonal and interannual CHL-<em>a </em>variability peaks in boreal summer and shows maxima in the equatorial Atlantic region at 10˚W, spreading from 0 to 30˚W. In this study, we analyze how the remotely-sensed surface CHL-<em>a </em>responds to the leading climate modes affecting the interannual equatorial Atlantic variability over the 1998-2018 period, namely the Atlantic Zonal Mode (AZM) and the North Tropical Atlantic Mode (NTA, also known as the Atlantic Meridional Mode). The AZM is characterized by anomalous warming (or cooling) along the eastern equatorial band. In contrast, the NTA is characterized by an interhemispheric pattern of the sea surface temperature (SST), with anomalous warm (cold) conditions in the north tropical Atlantic region and weak negative (positive) SST anomalies south of the equator. We show that both modes significantly drive the interannual Tropical Atlantic surface CHL-<em>a </em>variability, with different timings and contrasted modulation on the eastern and western portions of the cold tongue area. Our results also reveal that the NTA slightly dominates (40%) the summer tropical Atlantic interannual variability over the last two decades, most probably because of a positive phase of the Atlantic multidecadal oscillation. For each mode of variability, we analyze an event characterized by an extreme negative sea surface temperature (SST) anomaly in the Atlantic equatorial band. Both modes are associated with a positive CHL-<em>a </em>anomaly at the equator. In 2002, a negative phase of the NTA led to cold SST anomaly and high positive CHL-<em>a </em>in the western portion of the cold tongue, peaking in June-July and lasting until the end of the year. In contrast, in 2005, a negative phase of the AZM drove cool temperature and positive CHL-<em>a </em>in the eastern equatorial band, with a peak in May-June and almost no signature after August. Such contrasted year to year conditions can affect the marine ecosystem by changing temporal and spatial trophic niches for pelagic predators, thus inducing significant variations for ecosystem functioning and fisheries.</span></div>

Sign in / Sign up

Export Citation Format

Share Document