scholarly journals Long-term Variability of the Salinity Field in a Large Tropical, Well-Mixed Estuary: the Influence of Climatic Trends

2021 ◽  
Author(s):  
Rafael Mariani ◽  
Guilherme C. Lessa ◽  
Martinho Marta-Almeida
Keyword(s):  
Salinity Field ◽  
Climatic Trends

scholarly journals Documentary data and the study of past droughts: a global state of the art

2018 ◽  
Vol 14 (12) ◽  
pp. 1915-1960 ◽  
Author(s):  
Rudolf Brázdil ◽  
Andrea Kiss ◽  
Jürg Luterbacher ◽  
David J. Nash ◽  
Ladislava Řezníčková
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Drought Indices ◽  
Documentary Evidence ◽  
Climatic Trends ◽  
Instrumental Observations ◽  
Spatio Temporal ◽  
Epigraphic Evidence ◽  
Administrative Evidence

Abstract. The use of documentary evidence to investigate past climatic trends and events has become a recognised approach in recent decades. This contribution presents the state of the art in its application to droughts. The range of documentary evidence is very wide, including general annals, chronicles, memoirs and diaries kept by missionaries, travellers and those specifically interested in the weather; records kept by administrators tasked with keeping accounts and other financial and economic records; legal-administrative evidence; religious sources; letters; songs; newspapers and journals; pictographic evidence; chronograms; epigraphic evidence; early instrumental observations; society commentaries; and compilations and books. These are available from many parts of the world. This variety of documentary information is evaluated with respect to the reconstruction of hydroclimatic conditions (precipitation, drought frequency and drought indices). Documentary-based drought reconstructions are then addressed in terms of long-term spatio-temporal fluctuations, major drought events, relationships with external forcing and large-scale climate drivers, socio-economic impacts and human responses. Documentary-based drought series are also considered from the viewpoint of spatio-temporal variability for certain continents, and their employment together with hydroclimate reconstructions from other proxies (in particular tree rings) is discussed. Finally, conclusions are drawn, and challenges for the future use of documentary evidence in the study of droughts are presented.

Do tree ring δ13C series from Pinus sylvestris in northern Fennoscandia contain long-term non-climatic trends?

2008 ◽  
Vol 252 (1-2) ◽  
pp. 42-51 ◽  
Author(s):  
Mary Gagen ◽  
Danny McCarroll ◽  
Iain Robertson ◽  
Neil J. Loader ◽  
Risto Jalkanen
Keyword(s):  
Pinus Sylvestris ◽  
Tree Ring ◽  
Climatic Trends ◽  
Northern Fennoscandia

The long-term salinity field in San Francisco Bay

1996 ◽  
Vol 16 (15) ◽  
pp. 2005-2039 ◽  
Author(s):  
R.J. Uncles ◽  
D.H. Peterson
Keyword(s):  
San Francisco ◽  
San Francisco Bay ◽  
Salinity Field

scholarly journals Seawater Salinity Estimating Module Based on the Sound Velocity Measurements

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
А. P. Tolstosheev ◽  
E. G. Lunev ◽  
S. V. Motyzhev ◽  
V. Z. Dykman ◽  
◽  
...  
Keyword(s):  
Sound Velocity ◽  
Ocean Dynamics ◽  
Sea Surface ◽  
Temperature Measurements ◽  
Velocity Measurements ◽  
In Situ Tests ◽  
Salinity Field ◽  
In Situ Observations

Purpose. Reliability of knowledge about the ocean dynamics and climate variability is largely limited for lack of systematic in situ observations of the sea surface layer salinity, which is one of the basic hydrological parameters determining circulation and stratification of the water masses. The study is aimed at developing an autonomous device for long-term monitoring of salinity in the seawater upper layer. Methods and Results. One of the most effective tools for in situ observations of the ocean upper layer is the global network of surface drifting buoys – drifters. At present, the network consists of more than 1500 buoys, but only a few of them provide sea surface salinity observations within the framework of a limited number of pilot experiments. In the drifters, salinity is calculated by the traditional method using the results of the electrical conductivity and temperature measurements. There are a few problems related both to the principle of determining salinity by this method and to providing long-term stable running of conductivity sensors under the conditions of pollution and biological fouling. A drifter equipped with the module for the sound velocity and temperature measurements used for calculating salinity by an alternative method just aboard the drifter, was developed in Marine Hydrophysical Institute, Russian Academy of Sciences. The sound velocity and temperature module includes a specially designed time-of-flight sound velocity sensor with the fixed base and a quartz temperature sensor. In course of two years, numerous laboratory and in situ tests of several prototypes of the sound velocity and temperature module were performed. The laboratory tests showed that the repeatability limits for the results of the sound velocity measurements in the distilled water were 0.02 m/s. According to the data of the long-term in situ tests performed at intensive biological fouling, the error of salinity estimation resulted from of the sound velocity and temperature measurements were within 0.05 ‰. This result permits to expect that the sound velocity and temperature module parameters will remain stable in real conditions of long-term autonomous operation. Conclusions. The obtained results make it possible to recommend application of the drifters equipped with the modules for the sound velocity and temperature measurements as an effective tool for regular operational monitoring of the salinity field of the upper sea layer.

scholarly journals THE NATURAL DYNAMICS OF THE DIVERSITY OF SMALL MAMMAL’S COMMUNITIES IN PRIMARY FORESTS IN THE CENTRAL OF THE CASPIAN-BALTIC WATERSHED

2017 ◽  
Vol 1 ◽  
pp. 121
Author(s):  
Anatoly Istomin ◽  
Sergey Mikhalap
Keyword(s):  
Biosphere Reserve ◽  
Southern Taiga ◽  
Gis Analysis ◽  
Climatic Trends ◽  
Β Diversity ◽  
Natural Dynamics ◽  
Gradient Approach ◽  
Primary Forests ◽  
The Continuum

Diversity is one of the main characteristics of the system, which reflects its complexity and structure. Diversity of biotic communities is always being actively discussed in the consideration of their organization, functioning, and sustainability. However, many questions still remain debatable. The report deals with the results of long-term (1980-2015) studies of the diversity of micromammalia communities in the primary ecosystems of southern Taiga of the Central Forest State Natural Biosphere Reserve (Russia), which is located in the centre of the Caspian-Baltic watershed. The diversity change of small mammals’ communities was connected with climatic trends, extreme and catastrophic climatic phenomena. The authors offer methods of research and evaluation of α - and β-diversity of communities in conditions of the continuum of the environment of primary forests with the use of the gradient approach and GIS analysis.

Pollen and macrofossil evidence of Late Pleistocene and Holocene treeline fluctuations from an alpine lake in Colorado, USA

The Holocene ◽  
2012 ◽  
Vol 23 (1) ◽  
pp. 68-77 ◽  
Author(s):  
Gonzalo Jiménez-Moreno ◽  
R Scott Anderson
Keyword(s):  
Magnetic Susceptibility ◽  
Younger Dryas ◽  
Winter Precipitation ◽  
Alpine Lake ◽  
Climatic Trends ◽  
Lake Sediment Core ◽  
Lodgepole Pines ◽  
Pinus Aristata ◽  
Climate Cooling

High-resolution pollen, plant macrofossil and magnetic susceptibility (MS) data are presented from an alpine lake sediment core from west-central Colorado, recording changes in vegetation and sedimentation for the latest Pleistocene and Holocene ( c. the last 12.5 ka; 1 ka = 1000 cal. yr BP). During the Younger Dryas chron ( c. 12.9–11.5 ka), Artemisia steppe or tundra grew around the lake, but by the earliest Holocene (10.7–9.5 ka) a subalpine Picea and Abies parkland was established there. Picea remained important through the early Holocene, but also bristlecone and lodgepole pines ( Pinus aristata and P. contorta) grew around the lake. Warming conditions are indicated from 9.5 ka, lasting until c. 4.5–3.5 ka, which may have been the warmest period, with greatest development of monsoonal conditions. Trees subsequently retreated downslope from Kite Lake c. 150–200 m during the last 3.5 ka, establishing their present treeline position. A decrease in total Pinus and increases in Artemisia and piñon ( P. edulis) indicate a trend toward progressive climate cooling and enhanced winter precipitation. These long-term climatic trends correlate with Holocene changes in summer insolation.

scholarly journals Toward Estimating Climatic Trends in SST. Part I: Methods of Measurement

2006 ◽  
Vol 23 (3) ◽  
pp. 464-475 ◽  
Author(s):  
Elizabeth C. Kent ◽  
Peter K. Taylor
Keyword(s):  
Measurement Method ◽  
Early Period ◽  
Sea Surface ◽  
Data Set ◽  
Climatic Trends ◽  
The Pacific ◽  
The Mean ◽  
Seasonal Signal ◽  
Long Term Trend

Abstract To assess climatic changes in sea surface temperature (SST), changes in the measurement method with time and the effect of these changes on the mean SST must be quantified. Observations from the International Comprehensive Ocean–Atmosphere Data Set (ICOADS) have been analyzed for the period from 1970 to 1997 using both SST measurement metadata contained within the dataset and a World Meteorological Organization (WMO) catalog of observing ships. The WMO metadata were particularly important in identifying engine-intake SSTs during the 1970s, but increased method identification over the entire period. There are strong regional variations in the preferred SST measurement method, with engine-intake SST most common in the Pacific and bucket SST preferred by countries bordering the Atlantic. The number of engine-intake SSTs increases over time and becomes more numerous than buckets by the early 1980s. There are significant differences between SST observations made by different methods. The rounding of reports is more common for engine-intake SST than for either bucket or hull sensor SST, which degrades its quality. Significant time-varying biases exist between SST derived from buckets and from engine intakes. The SST difference has a strong seasonal signal with bucket SST being relatively cold in winter, probably resulting from heat loss from the buckets, and warm in summer, probably resulting from solar warming or the sampling of a shallow warm layer. There is also a long-term trend with engine-intake SST being relatively warm in the early period but with a small annual mean difference between the two methods by 1990.

scholarly journals Flotation and retreat of a lake-calving terminus, Mendenhall Glacier, southeast Alaska, USA

2007 ◽  
Vol 53 (181) ◽  
pp. 211-224 ◽  
Author(s):  
Eleanor S. Boyce ◽  
Roman J. Motyka ◽  
Martin Truffer
Keyword(s):  
Lake Level ◽  
Large Scale ◽  
Polar Ice ◽  
Southeast Alaska ◽  
Tidewater Glaciers ◽  
Climatic Trends ◽  
Bedrock Topography ◽  
Break Up

AbstractMendenhall Glacier is a lake-calving glacier in southeastern Alaska, USA, that is experiencing substantial thinning and increasingly rapid recession. Long-term mass wastage linked to climatic trends is responsible for thinning of the lower glacier and leaving the terminus vulnerable to buoyancy-driven calving and accelerated retreat. Bedrock topography has played a major role in stabilizing the terminus between periods of rapid calving and retreat. Lake-terminating glaciers form a population distinct from both tidewater glaciers and polar ice tongues, with some similarities to both groups. Lacustrine termini experience fewer perturbations (e.g. tidal flexure, high subaqueous melt rates) and are therefore inherently more stable than tidewater termini. At Mendenhall, rapid thinning and simultaneous retreat into a deeper basin led to flotation conditions along approximately 50% of the calving front. This unstable terminus geometry lasted for approximately 2 years and culminated in large-scale calving and terminus collapse during summer 2004. Buoyancy-driven calving events and terminus break-up can result from small, rapidly applied perturbations in lake level.

Sign in / Sign up

Export Citation Format

Share Document