The relative contribution of fluctuations in relative humidity and particulate concentrations to the variability of the scattering coefficient over the North Atlantic

1981 ◽  
Vol 15 (3) ◽  
pp. 415 ◽  
Author(s):  
J.A. Ogren ◽  
R.J. Charlson ◽  
D.S. Covert
Keyword(s):  
Relative Humidity ◽  
North Atlantic ◽  
Scattering Coefficient ◽  
The North ◽  
Relative Contribution ◽  
The North Atlantic

scholarly journals A twenty-year study on natural and manmade global interannual fluctuations of cirrus cloud cover

2007 ◽  
Vol 7 (1) ◽  
pp. 93-126 ◽  
Author(s):  
K. Eleftheratos ◽  
C. S. Zerefos ◽  
P. Zanis ◽  
D. S. Balis ◽  
G. Tselioudis ◽  
...  
Keyword(s):  
Relative Humidity ◽  
North Atlantic ◽  
Annual Cycle ◽  
Cloud Cover ◽  
Cirrus Cloud ◽  
The North ◽  
Long Term Trends ◽  
The North Atlantic ◽  
The Tropics

Abstract. The seasonal variability and the interannual variance explained by ENSO and NAO to cirrus cloud cover (CCC) are examined during the twenty-year period 1984–2004. CCC was found to be significantly correlated with vertical velocities and relative humidity from ECMWF/ERA40 in the tropics (correlations up to –0.7 and +0.7 at some locations, respectively) suggesting that variations in large-scale vertical winds and relative humidity fields can be the origin of up to half of the local variability in CCC over these regions. These correlations reflect mostly the seasonal cycle. Although the annual cycle is dominant in all latitudes and longitudes, peaking over the tropics and subtropics, its amplitude can be exceeded during strong El Nino/La Nina events. Over the eastern tropical Pacific Ocean the interannual variance of CCC which can be explained by ENSO is about 6.8% and it is ~2.3 times larger than the amplitude of the annual cycle. Natural long-term trends in the tropics are generally small (about –0.3% cloud cover per decade) and possible manmade trends in those regions are also small. The contributions of NAO and QBO to the variance of CCC in the tropics are also small. In the northern mid–latitudes, on the other hand, the effect of NAO is more significant and can be very important regionally. Over northern Europe and the eastern part of the North Atlantic Flight Corridor (NAFC) there is a small positive correlation between CCC and NAO index during the wintertime of about 0.3. In this region, the interannual variance of CCC explained by NAO is 2.6% and the amplitude of the annual cycle is 3.1%. Long-term trends over this region are about +1.6% cloud cover per decade and compare well with the observed manmade trends over congested air traffic regions in Europe and the North Atlantic as have been evidenced from earlier findings.

scholarly journals A study on natural and manmade global interannual fluctuations of cirrus cloud cover for the period 1984–2004

2007 ◽  
Vol 7 (10) ◽  
pp. 2631-2642 ◽  
Author(s):  
K. Eleftheratos ◽  
C. S. Zerefos ◽  
P. Zanis ◽  
D. S. Balis ◽  
G. Tselioudis ◽  
...  
Keyword(s):  
Relative Humidity ◽  
North Atlantic ◽  
Annual Cycle ◽  
Cloud Cover ◽  
Cirrus Cloud ◽  
The North ◽  
Long Term Trends ◽  
The North Atlantic ◽  
The Tropics

Abstract. The seasonal variability and the interannual variance explained by ENSO and NAO to cirrus cloud cover (CCC) are examined during the twenty-year period 1984–2004. CCC was found to be significantly correlated with vertical velocities and relative humidity from ECMWF/ERA40 in the tropics (correlations up to −0.7 and +0.7 at some locations, respectively) suggesting that variations in large-scale vertical winds and relative humidity fields can be the origin of up to half of the local variability in CCC over these regions. These correlations reflect mostly the seasonal cycle. Although the annual cycle is dominant in all latitudes and longitudes, peaking over the tropics and subtropics, its amplitude can be exceeded during strong El Nino/La Nina events. Over the eastern tropical Pacific Ocean the interannual variance of CCC which can be explained by ENSO is about 6.8% and it is ~2.3 times larger than the amplitude of the annual cycle. Natural long-term trends in the tropics are generally small (about −0.3% cloud cover per decade) and possible manmade trends in those regions are also small. The contributions of NAO and QBO to the variance of CCC in the tropics are also small. In the northern mid-latitudes, on the other hand, the effect of NAO is more significant and can be very important regionally. Over northern Europe and the eastern part of the North Atlantic Flight Corridor (NAFC) there is a small positive correlation between CCC and NAO index during the wintertime of about 0.3. In this region, the interannual variance of CCC explained by NAO is 2.6% and the amplitude of the annual cycle is 3.1%. Long-term trends over this region are about +1.6% cloud cover per decade and compare well with the observed manmade trends over congested air traffic regions in Europe and the North Atlantic as have been evidenced from earlier findings.

scholarly journals Climatic controls on water vapor deuterium excess in the marine boundary layer of the North Atlantic based on 500 days of in situ, continuous measurements

2014 ◽  
Vol 14 (2) ◽  
pp. 2363-2401 ◽  
Author(s):  
H. C. Steen-Larsen ◽  
A. E. Sveinbjörnsdottir ◽  
A. J. Peters ◽  
V. Masson-Delmotte ◽  
M. P. Guishard ◽  
...  
Keyword(s):  
Water Vapor ◽  
Wind Speed ◽  
Relative Humidity ◽  
North Atlantic ◽  
Deuterium Excess ◽  
The North ◽  
Hourly Data ◽  
The North Atlantic ◽  
The Relationship

Abstract. Continuous, in situ measurements of water vapor isotopic composition have been conducted in the North Atlantic, Bermuda Islands (32.26° N, 64.88° W) between November 2011 and June~2013, using a~cavity-ring-down-spectrometer water vapor isotope analyzer and an autonomous self-designed calibration system. Meticulous calibration allows us to reach an accuracy and precision on 10 min average of δ18O, δD, and d-excess of respectively 0.14 ‰, 0.85 ‰, and 1.1 ‰, verified using two parallel instruments with independent calibration. As a result of more than 500 days with 6 hourly data the relationships between deuterium excess, relative humidity (rh), sea surface temperature (SST), wind speed and direction are assessed. From the whole dataset, 84% of d-excess variance is explained by a strong linear relationship with relative humidity. The slope of this relationship (−42.6 ± 0.4 ‰ % (rh)) is similar to the theoretical prediction of Merlivat and Jouzel (1979) for SST between 20 °C and 30 °C. However, in contrast with theory, no effect of wind speed could be detected on the relationship between d-excess and relative humidity. Separating the dataset into winter, spring, summer, and autumn seasons reveals different linear relationships between d-excess and humidity. Changes in wind directions are observed to affect the relationships between d-excess and humidity. The observed seasonal variability in the relationship between d-excess and relative humidity underlines the importance of long-term monitoring to make accurate conclusions.

scholarly journals Climatic controls on water vapor deuterium excess in the marine boundary layer of the North Atlantic based on 500 days of in situ, continuous measurements

2014 ◽  
Vol 14 (15) ◽  
pp. 7741-7756 ◽  
Author(s):  
H. C. Steen-Larsen ◽  
A. E. Sveinbjörnsdottir ◽  
A. J. Peters ◽  
V. Masson-Delmotte ◽  
M. P. Guishard ◽  
...  
Keyword(s):  
Water Vapor ◽  
Wind Speed ◽  
Relative Humidity ◽  
North Atlantic ◽  
Deuterium Excess ◽  
Data Set ◽  
The North ◽  
The North Atlantic ◽  
The Relationship

Abstract. Continuous, in situ measurements of water vapor isotopic composition have been conducted in the North Atlantic, at the Bermuda Islands (32.26° N, 64.88° W), between November 2011 and June 2013, using a cavity ring-down spectrometer water vapor isotope analyzer and an autonomous self-designed calibration system. Meticulous calibration allows us to reach an accuracy and precision on 10 min average of δ18O, δ D, and d-excess of, 0.14, 0.85, and 1.1‰, verified using two parallel instruments with independent calibration. As a result of more than 500 days with 6-hourly data the relationships between deuterium excess, relative humidity (RH), sea surface temperature (SST), wind speed, and wind direction are assessed. From the whole data set, 84 % of d-excess variance is explained by a strong linear relationship with relative humidity. The slope of this relationship (−42.6 ± 0.4‰ % (RH)) is similar to the theoretical prediction of Merlivat and Jouzel (1979) for SST between 20 and 30 °C. However, in contrast with theory, no effect of wind speed could be detected on the relationship between d-excess and relative humidity. Separating the data set into winter, spring, summer, and autumn seasons reveals different linear relationships between d-excess and humidity. Changes in wind directions are observed to affect the relationships between d-excess and humidity. The observed seasonal variability in the relationship between d-excess and relative humidity underlines the importance of long-term monitoring to make accurate conclusions.

Analysis of statistical correlation between the indices of the most determinant ocean-atmospheric patterns in the climatology of the North Atlantic-Western Europe (NA-WE)

2021 ◽  
Author(s):  
Pedro San Martin Orbe
Keyword(s):  
Relative Humidity ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
Western Europe ◽  
Statistical Correlation ◽  
Winter Period ◽  
The South ◽  
Annual Series ◽  
The North ◽  
The North Atlantic

<p>South situations or days in which the South Wind (SE-S-SW) constitutes the predominant wind direction (mode) and one of the factors more determinants of the climatic conditions in terms of temperature and relative humidity in the autumn-winter period of the geographical region of southwestern Europe around the central territorial axis of the Bay of Biscay-Gascony.</p><p>According to our conclusions on the official data analyzed in thirteen meteorological stations in this region of southwestern Europe, for the 1961-2010 annual series, more than 43% of the autumn-winter days with prevailing winds from the South, or South Wind, register average temperature values ​​(T) higher than their respective autumn-winter average. Likewise, in eleven of the thirteen stations analyzed, for the same annual series, the average relative humidity (H) record corresponding to the set of autumn-winter days with predominant South Wind is lower than the respective mid autumn-winter and in the other two seasons both records are equal.</p><p>In the stations of the coastal region, such as Bilbao and Gijón, for the 1961-71 annual series, with an atmospheric circulation characterized, in all autumn-winter periods, by negative mean values ​​of the North Atlantic Oscillation index (NAO), the percentage frequency of South Wind situations is higher than that corresponding to the coastal stations of San Sebastián, Santander and Biarritz in the 1971-2010  annual series, as well as with respect to the percentage frequency for any other station and in both series.</p><p>The climatic and environmental conditions of this region of southwestern Europe are strongly affected by the tempering influence of the South Atlantic winds, following a process of orographic condensation-desiccation to windward and subsidence, adiabatic compression and rapid movement along the slopes, downwind of the Cantabrian-Pyrenean mountain range (Foehn effect).</p><p>Thus, the general atmospheric circulation over the region favors, especially in the autumn-winter period, the advections of humid and unstable air masses (storms and fronts) coming from the middle and subtropical latitudes of the North Atlantic, which generate anabatic south winds on the Iberian Peninsula, heading towards the Western Cantabrian-Pyrenean region and through it towards the continental Atlantic façade, but already more tempered and parched.</p><p>These southern situations are generated under conditions of atmospheric circulation and synoptic configuration defined by the interrelation between multiple oceanic and atmospheric patterns (in addition to solar, orographic factors...) that also largely determine the climatology of the entire oceanic and continental North Atlantic región.</p><p>As a great diversity of studies carried out have been collecting and demonstrating, the ocean-atmospheric patterns, both planetary and regional (ENSO, AMO, NAO, WeMO...) and the teleconnection between events or climatic phenomena generated by they and even in a very distant between them, constitute fundamental factors to define the atmospheric circulation and the climatology of the North Atlantic-Western Europe region (NAWE).</p><p>The empirical vision of the teleconnection between these ocean-atmospheric patterns requires the analysis of the significant statistical correlation coefficients between the indices of such factors or patterns, for which we will use the integrated program or set of programs "R".</p><p> </p><p>                             </p>

The Currents of the North Atlantic

1892 ◽  
Vol 34 (872supp) ◽  
pp. 13940-13941
Author(s):  
Richard Beynon
Keyword(s):  
North Atlantic ◽  
The North ◽  
The North Atlantic

NATO adaptation to current challenges and mechanisms of Ukraine’s cooperation with the North Atlantic Treaty Organization

2019 ◽  
pp. 73-81
Author(s):  
Oleh Poshedin
Keyword(s):  
North Atlantic ◽  
Task Force ◽  
Response Force ◽  
Cyber Attack ◽  
Adaptation Measures ◽  
Joint Force ◽  
Security Environment ◽  
The North ◽  
The North Atlantic ◽  
Area Of Influence

The purpose of the article is to describe the changes NATO undergoing in response to the challenges of our time. Today NATO, as a key element of European and Euro-Atlantic security, is adapting to changes in the modern security environment by increasing its readiness and ability to respond to any threat. Adaptation measures include the components required to ensure that the Alliance can fully address the security challenges it might face. Responsiveness NATO Response Force enhanced by developing force packages that are able to move rapidly and respond to potential challenges and threats. As part of it, was established a Very High Readiness Joint Task Force, a new Allied joint force that deploy within a few days to respond to challenges that arise, particularly at the periphery of NATO’s territory. NATO emphasizes, that cyber defence is part of NATO’s core task of collective defence. A decision as to when a cyber attack would lead to the invocation of Article 5 would be taken by the North Atlantic Council on a case-by-case basis. Cooperation with NATO already contributes to the implementation of national security and defense in state policy. At the same time, taking into account that all decision-making in NATO based on consensus, Ukraine’s membership in the Alliance quite vague perspective. In such circumstances, in Ukraine you often can hear the idea of announcement of a neutral status. It is worth reminding that non-aligned status did not save Ukraine from Russian aggression. Neutral status will not accomplish it either. All talks about neutrality and the impossibility of Ukraine joining NATO are nothing but manipulations, as well as recognition of the Ukrainian territory as Russian Federation area of influence (this country seeks to sabotage the Euro-Atlantic movement of Ukraine). Think about it, Moldova’s Neutrality is enshrined in the country’s Constitution since 1994. However, this did not help Moldova to restore its territorial integrity and to force Russia to withdraw its troops and armaments from Transnistria.

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