Tag Archives: oceans

Solar activity, atmospheric-oceanic variability drives temperatures

LIANG JIAO, SHENGJIE WANG, YUAN JIANG, XUERUI LIU. A 333-YEAR RECORD OF THE MEAN MINIMUM TEMPERATURE RECONSTRUCTION IN THE WESTERN TIANSHAN MOUNTAINS, CHINA. GEOCHRONOMETRIA 46 (2019): 37–48 DOI 10.1515/geochr-2015-0104

 

In this paper, a fragile ecological area in the Western Tianshan National Nature Reserve of China was selected as the research region, and Picea schrenkiana, which is sensitive to climate change, was selected as the research object. The mean minimum temperature in the growing season of the previous year (May to September) was the main limiting factor for tree radial growth based on an analysis of the relationship between chronological series and climatic factors during 1959–2012 (r = –0.792, p < 0.05). Moreover, the relationship was stable, which showed that tree rings can be used as alternative materials for climate reconstruction. Therefore, the mean minimum temperature of the previous year in 1680–2012 was reconstructed, and the explained variance of the reconstruction equation was 62.7% (R2adj = 62.0%, F = 85.8). The 31 dramatically altered years were found via char- acteristic year analyses, and extreme changes occurred most often under relatively warm conditions. The mean minimum temperature in the reconstruction shows a clear warming trend by the 11-year moving average of the reconstructive series since the 1950s (the temperature increase: 0.341°C/decade). The driving factors of the mean minimum temperature were influenced mainly by the interaction of solar activity and large-scale atmospheric–oceanic variability, especially the westerly circulations.

The Great Barrier Reef adapts to ecosystem changes

“The Great Barrier Reef spans 2,000 kilometers and five degrees Celsius from 27 to 32°C and we’re still finding reefs we didn’t even know about. The pH swings on a daily basis, and fish do better when it does. One coral has adapted to ocean “acidification” in 6 months. Other fish remarkably adapted from salt to freshwater in just fifty years. As Peter Ridd says: Of all the ecosystems in the world, the reef is one that’s best at adapting to climate change.click here

World ocean accounts for ~93% of global warming since 1955

J. I. Antonov, T. P. Boyer, O. K. Baranova, H. E. Garcia World ocean heat content and thermosteric sea level change (0–2000 m), 1955–2010. Geophysical Research Letters, 17 May 2012. https://doi.org/10.1029/2012GL051106

[1] We provide updated estimates of the change of ocean heat content and the thermosteric component of sea level change of the 0–700 and 0–2000 m layers of the World Ocean for 1955–2010. Our estimates are based on historical data not previously available, additional modern data, and bathythermograph data corrected for instrumental biases. We have also used Argo data corrected by the Argo DAC if available and used uncorrected Argo data if no corrections were available at the time we downloaded the Argo data. The heat content of the World Ocean for the 0–2000 m layer increased by 24.0 ± 1.9 × 1022 J (±2S.E.) corresponding to a rate of 0.39 W m−2 (per unit area of the World Ocean) and a volume mean warming of 0.09°C. This warming corresponds to a rate of 0.27 W m−2 per unit area of earth’s surface. The heat content of the World Ocean for the 0–700 m layer increased by 16.7 ± 1.6 × 1022 J corresponding to a rate of 0.27 W m−2(per unit area of the World Ocean) and a volume mean warming of 0.18°C. The World Ocean accounts for approximately 93% of the warming of the earth system that has occurred since 1955. The 700–2000 m ocean layer accounted for approximately one‐third of the warming of the 0–2000 m layer of the World Ocean. The thermosteric component of sea level trend was 0.54 ± .05 mm yr−1for the 0–2000 m layer and 0.41 ± .04 mm yr−1 for the 0–700 m layer of the World Ocean for 1955–2010.

 

Oceans have warmed 0.021°C since 1994

Carl Wunsch. Towards determining uncertainties in global oceanic mean values of heat, salt, and surface elevation. Journal Tellus A: Dynamic Meteorology and Oceanography. Volume 70, 2018 – Issue 1 https://doi.org/10.1080/16000870.2018.1471911

Lower-bounds on uncertainties in oceanic data and a model are calculated for the 20-year time means and their temporal evolution for oceanic temperature, salinity, and sea surface height, during the data-dense interval 1994–2013. The essential step of separating stochastic from systematic or deterministic elements of the fields is explored by suppressing the globally correlated components of the fields. Justification lies in the physics and the brevity of a 20-year estimate relative to the full oceanic adjustment time, and the inferred near-linearity of response on short time intervals. Lower-bound uncertainties reflecting the only stochastic elements of the state estimate are then calculated from bootstrap estimates. Trends are estimated as 2.2±0.2mm/y in elevation, 0.0011 ±  0.0001 °C/y, and (−2.825 ± 0.17) × 10−5 for surface elevation, temperature and salt, with formal 2-standard deviation uncertainties. The temperature change corresponds to a 20-year average ocean heating rate of 0.48±0.1 W/m2 of which 0.1 W/m2 arises from the geothermal forcing. Systematic errors must be determined separately.

IPCC “changing Gulf Stream” orthodoxy falsified.

“A huge circulation pattern in the Atlantic Ocean took a starring role in the 2004 movie “The Day After Tomorrow.” In that fictional tale the global oceanic current suddenly stops and New York City freezes over. While many aspects of the movie are unrealistic, oceanographers are concerned about the long-term stability of the Atlantic Ocean circulation, and previous studies show that it has slowed dramatically in the past decade. New research from the University of Washington and the Ocean University of China finds the slowdown is not caused by global warming but is part of regular, decades-long cycle that will affect temperatures in coming decades.” click here

Southern ocean temperature pattern refutes climate models

“The IPCC report said “Feedbacks associated with changes in sea ice and snow amplify surface warming near the poles” and gave several supporting references. But the Southern Oceans temperature pattern above shows the exact opposite: the further south you get, the greater the rate of cooling. In fact, at almost the precise latitude where the IPCC expected the most amplified warming there was some of the fastest cooling on the planet! [Note where zero trend is on the Y axis].” click here

Sea surface temperature drives global climate

Andrea J. Dittus et al. Understanding the role of sea surface temperature-forcing for variability in global temperature and precipitation extremes. Weather and Climate Extremes Volume 21, September 2018, Pages 1-9.

The oceans are a well-known source of natural variability in the climate system, although their ability to account for inter-annual variations of temperature and precipitation extremes over land remains unclear. In this study, the role of sea-surface temperature (SST)-forcing is investigated for variability and trends in a range of commonly used temperature and precipitation extreme indices over the period 1959 to 2013. Using atmospheric simulations forced by observed SST and sea-ice concentrations (SIC) from three models participating in the Climate of the Twentieth Century Plus (C20C+) Project, results show that oceanic boundary conditions drive a substantial fraction of inter-annual variability in global average temperature extreme indices, as well as, to a lower extent, for precipitation extremes. The observed trends in temperature extremes are generally well captured by the SST-forced simulations although some regional features such as the lack of warming in daytime warm temperature extremes over South America are not reproduced in the model simulations. Furthermore, the models simulate too strong increases in warm day frequency compared to observations over North America. For extreme precipitation trends, the accuracy of the simulated trend pattern is regionally variable, and a thorough assessment is difficult due to the lack of locally significant trends in the observations. This study shows that prescribing SST and SIC holds potential predictability for extremes in some (mainly tropical) regions at the inter-annual time-scale.