The response of the thermal stratification of South Bay (Lake Huron) to climatic variability

1997 ◽  
Vol 54 (8) ◽  
pp. 1873-1882 ◽  
Author(s):  
J R King ◽  
B J Shuter ◽  
A P Zimmerman
Keyword(s):  
Thermal Structure ◽  
Climatic Variability ◽  
Warming Trend ◽  
Lake Huron ◽  
Thermal Gradients ◽  
Data Set ◽  
Mount Pinatubo ◽  
Recent Warming ◽  
Air Temperatures ◽  
Canonical Analyses

The 37-year record (1955-1992) of water temperature profiles and corresponding meteorology for South Bay (Lake Huron) provide an extensive empirical data set for the study of climate variability and corresponding alterations in lake thermal structure. Thermoclines became shallower over this period and epilimnetic temperatures increased. Canonical analyses correlated warm May-July air temperatures and high July-August solar radiation with warmer epilimnia, larger thermal gradients across the thermocline, and shallower thermoclines. Multivariate canonical scores indicate that these thermal responses have increased in parallel with the recent warming trend since the mid-1960s. Anomalous multivariate scores correspond to El Niño events, and an extreme low score corresponds to the Mount Pinatubo cooling effect of 1992.

scholarly journals Global data set of long-term summertime vertical temperature profiles in 153 lakes

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Rachel M. Pilla ◽  
Elizabeth M. Mette ◽  
Craig E. Williamson ◽  
Boris V. Adamovich ◽  
Rita Adrian ◽  
...  
Keyword(s):  
Time Series ◽  
Thermal Structure ◽  
Ecological Change ◽  
Thermal Gradients ◽  
Temperature Profiles ◽  
Vertical Temperature ◽  
Data Set ◽  
Long Term Trends

AbstractClimate change and other anthropogenic stressors have led to long-term changes in the thermal structure, including surface temperatures, deepwater temperatures, and vertical thermal gradients, in many lakes around the world. Though many studies highlight warming of surface water temperatures in lakes worldwide, less is known about long-term trends in full vertical thermal structure and deepwater temperatures, which have been changing less consistently in both direction and magnitude. Here, we present a globally-expansive data set of summertime in-situ vertical temperature profiles from 153 lakes, with one time series beginning as early as 1894. We also compiled lake geographic, morphometric, and water quality variables that can influence vertical thermal structure through a variety of potential mechanisms in these lakes. These long-term time series of vertical temperature profiles and corresponding lake characteristics serve as valuable data to help understand changes and drivers of lake thermal structure in a time of rapid global and ecological change.

scholarly journals Circulation and heat budget in a regional climatological simulation of the Southwestern Tropical Atlantic.

2009 ◽  
Vol 37 (1-2) ◽  
Author(s):  
Marcus SILVA ◽  
Moacyr ARAÚJO ◽  
Jacques SERVAIN ◽  
Penven Pierrick
Keyword(s):  
Ocean Circulation ◽  
Heat Budget ◽  
Thermal Structure ◽  
Climatic Variability ◽  
Mixing Layer ◽  
Upper Ocean ◽  
Western Boundary ◽  
Tropical Atlantic ◽  
The South ◽  
Data Set

Surface and vertical thermal structures, heat budget in the surface mixing layer, and mass transports are explored in the south-western tropical Atlantic (5oS-25oS / 20oW-47oW). That region, where part of the South Equatorial Current (SEC) enters at its eastern border, is of prime interest by feeding many western boundary currents along the eastern Brazilian edge, and by contributing to the climatic variability over the Northeast Brazil. The Regional Ocean Model System (ROMS) is used here to simulate a seasonal cycle of the ocean circulation with an isotropic horizontal grid resolution of 1/12o and 40 terrain-following layers. Such a high-resolution regional model allows illustrating the complexity of meso-scales phenomena which occur in that region. Model results are compared with the very first annual series of observed thermal profiles available in the region thanks to the three PIRATA-SWE moorings recently deployed. Simulated thermal structure at the upper ocean layers agrees with in-situ data set. Seasonal evolutions of atmospheric and oceanic balances involving in the mixing layer heat budget are locally discussed. The magnitude of oceanic components (mainly the vertical diffusion and the horizontal advection) is about of the same order than of atmospheric forcing, and practically always opposes to it, with some local and seasonal timing differences. Simulated meridional transports across three zonal sections extending from continent to PIRATA sites provide new insight in the knowledge of the western boundary current system. Another section running along the PIRATA-SWE array indicates how the divergence of SEC is complex. This result encourages the need and future expansion of the observational PIRATA array system in that region. Keywords: South Western Tropical Atlantic, Upper Ocean layers, Ocean heat budget, PIRATA-SWE moorings, ROMS

A multi-proxy reconstruction of climate during the late-Pleistocene to early Holocene transition in the northeastern, USA

2021 ◽  
pp. 1-17
Author(s):  
Laurie D. Grigg ◽  
Kevin J. Engle ◽  
Alison J. Smith ◽  
Bryan N. Shuman ◽  
Maximilian B. Mandl
Keyword(s):  
Late Pleistocene ◽  
Climatic Variability ◽  
Warming Trend ◽  
Early Holocene ◽  
Individual Species ◽  
Environmental Preferences ◽  
The North ◽  
Show Evidence ◽  
Dry Conditions ◽  
Components Analysis

Abstract A multiproxy record from Twin Ponds, VT, is used to reconstruct climatic variability during the late Pleistocene to early Holocene transition. Pollen, ostracodes, δ18O, and lithologic records from 13.5 to 9.0 cal ka BP are presented. Pollen- and ostracode-inferred climatic reconstructions are based on individual species’ environmental preferences and the modern analog technique. Principal components analysis of all proxies highlights the overall warming trend and centennial-scale climatic variability. During the Younger Dryas cooling event (YD), multiple proxies show evidence for cold winter conditions and increasing seasonality after 12.5 cal ka BP. The early Holocene shows an initial phase of rapid warming with a brief cold interval at 11.5 cal ka BP, followed by a more gradual warming; a cool, wet period from 11.2 to 10.8 cal ka BP; and cool, dry conditions from 10.8 to 10.2 cal ka BP. The record ends with steady warming and increasing moisture. Post-YD climatic variability has been observed at other sites in the northeastern United States and points to continued instability in the North Atlantic during the final phases of deglaciation.

Manifestarea anotimpurilor în contextul schimbarilor climatice

2019 ◽  
Author(s):  
Maria Nedealcov ◽  
Keyword(s):  
Temporal Variability ◽  
Climatic Variability ◽  
Warming Trend ◽  
Climatic Parameters ◽  
Adaptation To Climate Change ◽  
Thermal Threshold ◽  
Average Temperature ◽  
Increasing Trend ◽  
Spatio Temporal ◽  
The Right

The early manifestation of the seasons and seasonal temperature's increasing trend for all seasons require adequate solutions of adaptation to climate change. Knowledge of the spatio-temporal variability of climatic parameters that characterize the seasons, focusing on the last decades - a period of time when climatic variability is even more pronounced compared to previous periods, is of particular interest. Analysis of the density of the seasonal average temperature distribution function indicates a shift to the right for the values, which demonstrates warming trend for all the seasons. The highest accelerated rhythm belongs to winters and summers, and in this context the duration of the seasons and the accumulation of daily temperatures with a certain thermal threshold is also changing.

scholarly journals Derivation and analysis of a high-resolution estimate of global permafrost zonation

2011 ◽  
Vol 5 (3) ◽  
pp. 1547-1582
Author(s):  
S. Gruber
Keyword(s):  
High Resolution ◽  
Land Surface ◽  
Permafrost Region ◽  
Large Area ◽  
Data Set ◽  
Regional Patterns ◽  
Actual Surface ◽  
Interesting Insight ◽  
Air Temperatures ◽  
Discontinuous Permafrost

Abstract. Permafrost underlies much of Earths' surface and interacts with climate, eco-systems and human systems. It is a complex phenomenon controlled by climate and (sub-) surface properties and reacts to change with variable delay. Heterogeneity and sparse data challenge the modeling of its spatial distribution. Currently, there is no data set to adequately inform global studies of permafrost. The available data set for the Northern Hemisphere is frequently used for model evaluation, but its quality and consistency are difficult to assess. A global model of permafrost extent and dataset of permafrost zonation are presented and discussed, extending earlier studies by including the Southern Hemisphere, by consistent data and methods, and most importantly, by attention to uncertainty and scaling. Established relationships between air temperature and the occurrence of permafrost are re-formulated into a model that is parametrized using published estimates. It is run with a high-resolution (<1 km) global elevation data and air temperatures based on the NCAR-NCEP reanalysis and CRU TS 2.0. The resulting data provides more spatial detail and a consistent extrapolation to remote regions, while aggregated values resemble previous studies. The estimated uncertainties affect regional patterns and aggregate number, but provide interesting insight. The permafrost area, i.e. the actual surface area underlain by permafrost, north of 60° S is estimated to be 13–18 × 106 km2 or 9–14 % of the exposed land surface. The global permafrost area including Antarctic and sub-sea permafrost is estimated to be 16–21 × 106 km2. The global permafrost region, i.e. the exposed land surface below which some permafrost can be expected, is estimated to be 22 ± 3 × 106 km2. A large proportion of this exhibits considerable topography and spatially-discontinuous permafrost, underscoring the importance of attention to scaling issues and heterogeneity in large-area models.

Tree-ring records from New Zealand: long-term context for recent warming trend

1998 ◽  
Vol 14 (3) ◽  
pp. 191-199 ◽  
Author(s):  
R. D. D'Arrigo ◽  
E. R. Cook ◽  
M. J. Salinger ◽  
J. Palmer ◽  
P. J. Krusic ◽  
...  
Keyword(s):  
New Zealand ◽  
Tree Ring ◽  
Warming Trend ◽  
Recent Warming

scholarly journals Deeper waters are changing less consistently than surface waters in a global analysis of 102 lakes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rachel M. Pilla ◽  
Craig E. Williamson ◽  
Boris V. Adamovich ◽  
Rita Adrian ◽  
Orlane Anneville ◽  
...  
Keyword(s):  
Surface Water ◽  
Average Rate ◽  
Thermal Structure ◽  
Global Analysis ◽  
Regional Climate ◽  
Data Set ◽  
Water Column Stability ◽  
Temperature Trends ◽  
Lake Characteristics

AbstractGlobally, lake surface water temperatures have warmed rapidly relative to air temperatures, but changes in deepwater temperatures and vertical thermal structure are still largely unknown. We have compiled the most comprehensive data set to date of long-term (1970–2009) summertime vertical temperature profiles in lakes across the world to examine trends and drivers of whole-lake vertical thermal structure. We found significant increases in surface water temperatures across lakes at an average rate of + 0.37 °C decade−1, comparable to changes reported previously for other lakes, and similarly consistent trends of increasing water column stability (+ 0.08 kg m−3 decade−1). In contrast, however, deepwater temperature trends showed little change on average (+ 0.06 °C decade−1), but had high variability across lakes, with trends in individual lakes ranging from − 0.68 °C decade−1 to + 0.65 °C decade−1. The variability in deepwater temperature trends was not explained by trends in either surface water temperatures or thermal stability within lakes, and only 8.4% was explained by lake thermal region or local lake characteristics in a random forest analysis. These findings suggest that external drivers beyond our tested lake characteristics are important in explaining long-term trends in thermal structure, such as local to regional climate patterns or additional external anthropogenic influences.

Morphofunctional changes to the phytoplankton community in tropical ecosystems during the El Niño event of 2015–16

2019 ◽  
Vol 70 (11) ◽  
pp. 1576
Author(s):  
F. H. P. C. de Oliveira ◽  
A. N. Moura ◽  
Ê. W. Dantas
Keyword(s):  
El Niño ◽  
El Nino ◽  
Climatic Variables ◽  
Arid Ecosystems ◽  
Filamentous Cyanobacteria ◽  
El Niño Event ◽  
Centric Diatoms ◽  
Air Temperatures ◽  
Semi Arid ◽  
Canonical Analyses

This study reports the effects of the El Niño event of 2015–16 on abiotic and biotic variables in tropical reservoirs in semi-arid and wet regions. Samples were collected in control years (2014) and during the El Niño event (2015–16). Phytoplankton was identified and its biomass quantified. Physicochemical and climatic variables were evaluated. Canonical analyses were performed to determine the effects of abiotic variables on phytoplankton. In semi-arid ecosystems, there was a decrease in diversity during the El Niño event, as well as an increase in the relative biomass of centric diatoms and a decrease in filamentous cyanobacteria. In wet ecosystems, changes in the community were not observed during the El Niño event. The synergistic contribution between physiochemical and climatic variables was most pronounced during the El Niño event in all ecosystems. Filamentous cyanobacteria were associated with the control year and favoured by higher pH values and sulfate concentrations. Centric diatoms were related to higher air temperatures and lower sulfate concentrations during the El Niño event. El Niño caused morphofunctional modifications to the phytoplankton in a distinct way in semi-arid and wet ecosystems. We show that in semi-arid reservoirs the El Niño event decreased the relative biomass of filamentous cyanobacteria and favoured central diatoms because of changes to sulfate concentrations.

The Southern Ocean and its interaction with the Antarctic Ice Sheet

Science ◽  
2020 ◽  
Vol 367 (6484) ◽  
pp. 1326-1330
Author(s):  
David M. Holland ◽  
Keith W. Nicholls ◽  
Aurora Basinski
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
Thermal Structure ◽  
Ice Sheet ◽  
Major Influence ◽  
Antarctic Ice Sheet ◽  
Ice Shelves ◽  
Air Temperatures ◽  
The Antarctic ◽  
Circulation Changes

The Southern Ocean exerts a major influence on the mass balance of the Antarctic Ice Sheet, either indirectly, by its influence on air temperatures and winds, or directly, mostly through its effects on ice shelves. How much melting the ocean causes depends on the temperature of the water, which in turn is controlled by the combination of the thermal structure of the surrounding ocean and local ocean circulation, which in turn is determined largely by winds and bathymetry. As climate warms and atmospheric circulation changes, there will be follow-on changes in the ocean circulation and temperature. These consequences will affect the pace of mass loss of the Antarctic Ice Sheet.

scholarly journals Variations in Winter Surface Temperature of the Purog Kangri Ice Field, Qinghai–Tibetan Plateau, 2001–2018, Using MODIS Data

2020 ◽  
Vol 12 (7) ◽  
pp. 1133
Author(s):  
Yufan Qie ◽  
Ninglian Wang ◽  
Yuwei Wu ◽  
An’an Chen
Keyword(s):  
Tibetan Plateau ◽  
Surface Temperature ◽  
Land Surface ◽  
Remote Sensing Data ◽  
Warming Trend ◽  
Data Set ◽  
Moderate Resolution ◽  
Ice Field ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Meteorological Observations

In the context of global warming, the land surface temperature (LST) from remote sensing data is one of the most useful indicators to directly quantify the degree of climate warming in high-altitude mountainous areas where meteorological observations are sparse. Using the daily Moderate Resolution Imaging Spectroradiometer (MODIS) LST product (MOD11A1 V6) after eliminating pixels that might be contaminated by clouds, this paper analyzes temporal and spatial variations in the mean LST on the Purog Kangri ice field, Qinghai–Tibetan Plateau, in winter from 2001 to 2018. There was a large increasing trend in LST (0.116 ± 0.05 °C·a−1) on the Purog Kangri ice field during December, while there was no evident LST rising trend in January and February. In December, both the significantly decreased albedo (−0.002 a−1, based on the MOD10A1 V6 albedo product) on the ice field surface and the significantly increased number of clear days (0.322 d·a−1) may be the main reason for the significant warming trend in the ice field. In addition, although the two highest LST of December were observed in 2017 and 2018, a longer data set is needed to determine whether this is an anomaly or a hint of a warmer phase of the Purog Kangri ice field in December.

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