Reconstructed 3-D Ocean Temperature Derived from Remotely Sensed Sea Surface Measurements for Mixed Layer Depth Analysis

The mixed layer depth (MLD) is generally estimated using in situ or model data. However, MLD analyses have limitations due to the sparse resolution of the observed data. Therefore, this study reconstructs three-dimensional (3D) ocean thermal structures using only satellite sea surface measurements for a higher spatial and longer temporal resolution than that of Argo and diagnoses the decadal variation of global MLD variability. To simulate the ocean thermal structures, the relationship between the ocean subsurface temperature and the sea surface fields was computed based on gridded Argo data. Based on this relationship, high spatial resolution and extended periods of satellite-derived altimeter, sea surface temperature (SST), and wind stress data were used to estimate the 3D ocean thermal structures with 0.25° spatial resolution and 26 standard depth levels (5–2000 m) for 24 years (1993–2016). Then, the MLD was calculated using a temperature threshold method (∆T = 0.2 °C) and correlated reasonably well (>0.9) with other MLD datasets. The extended 24-year data enabled us to analyze the decadal variability of the MLD. The global linear trend of the 24-year MLD is −0.110 m yr−1; however, from 1998 to 2012, the linear trend is −0.003 m yr−1 which is an order of magnitude smaller than that of other periods and corresponds to a global warming hiatus period. Via comparisons between the trends of the SST anomalies and the MLD anomalies, we tracked how the MLD trend changes in response to the global warming hiatus.

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Long-term trends of global marine primary and secondary aerosol production during the recent global warming hiatus (2000–2015)

10.5194/acp-2018-322 ◽

2018 ◽

Author(s):

Sang-Keun Song ◽

Zang-Ho Shon ◽

Yu-Na Choi ◽

Young-Baek Son ◽

Minsung Kang ◽

...

Keyword(s):

Global Warming ◽

Pacific Ocean ◽

Southern Ocean ◽

Atmospheric Aerosol ◽

Sea Surface ◽

Aerosol Loading ◽

Global Warming Hiatus ◽

Long Term Trends ◽

Warming Hiatus

Abstract. Long-term trends in global sea spray aerosol (SSA) emissions and dimethyl sulfide (DMS) fluxes from sea to air during the recent global warming hiatus (2000–2015) were analyzed using satellite observations and modelling data. The SSA emissions were estimated using a widely used whitecap method with sea surface temperature (SST) dependence. In addition, sea-to-air DMS fluxes were also used to quantify the secondary contributions of DMS through its sequential oxidation and gas-to-particle conversion. Aerosol optical depth (AOD) was estimated by an aerosol optical model using the number concentration of SSA and non-sea-salt sulfate from DMS. The estimated AOD, which was derived from the SSA and DMS emitted from the sea surface, was compared with satellite-derived AOD to quantify its (primary and secondary) contribution to atmospheric aerosol loading (i.e., observed AOD). Yearly global mean anomalies in DMS fluxes and AOD derived from SSA showed statistically significant downward trends during the recent global warming hiatus, whereas SSA emissions and AOD derived from DMS oxidation did not. In terms of regional trends, the decreases in SSA emissions during 2000–2015 occurred over the central Pacific Ocean, the Indian Ocean, and the Caribbean Sea, whereas upward trends in SSA emissions occurred over the tropical southeastern Pacific Ocean, the Southern Ocean, and the North Atlantic Ocean. DMS fluxes during the study period showed a clear downward trend over most regions of the global ocean. The estimates of the contributions of SSA (primary) and DMS (secondary) to atmospheric aerosol loading were 23–62% and 26–38%, respectively, with the largest primary contribution (~90%) over the Southern Ocean.

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The relative contributions of tropical Pacific sea surface temperatures and atmospheric internal variability to the recent global warming hiatus

Geophysical Research Letters ◽

10.1002/2017gl074273 ◽

2017 ◽

Vol 44 (15) ◽

pp. 7945-7954 ◽

Cited By ~ 23

Author(s):

Clara Deser ◽

Ruixia Guo ◽

Flavio Lehner

Keyword(s):

Global Warming ◽

Internal Variability ◽

Tropical Pacific ◽

Sea Surface ◽

Sea Surface Temperatures ◽

Surface Temperatures ◽

Global Warming Hiatus ◽

Warming Hiatus

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Characteristics of climate extremes in China during the recent global warming hiatus based upon machine learning

International Journal of Climatology ◽

10.1002/joc.7354 ◽

2021 ◽

Author(s):

Peihua Qin ◽

Chunxiang Shi

Keyword(s):

Machine Learning ◽

Global Warming ◽

Climate Extremes ◽

Global Warming Hiatus ◽

Warming Hiatus

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Response of the mixed layer depth and subduction rate in the subtropical Northeast Pacific to global warming

Acta Oceanologica Sinica ◽

10.1007/s13131-021-1818-y ◽

2021 ◽

Author(s):

Ruibin Xia ◽

Bingrui Li ◽

Cheng Chen

Keyword(s):

Global Warming ◽

Mixed Layer ◽

Mixed Layer Depth ◽

Layer Depth ◽

Northeast Pacific ◽

Subduction Rate

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A Link between the Hiatus in Global Warming and North American Drought

Journal of Climate ◽

10.1175/jcli-d-14-00616.1 ◽

2015 ◽

Vol 28 (9) ◽

pp. 3834-3845 ◽

Cited By ~ 69

Author(s):

Thomas L. Delworth ◽

Fanrong Zeng ◽

Anthony Rosati ◽

Gabriel A. Vecchi ◽

Andrew T. Wittenberg

Keyword(s):

Global Warming ◽

North America ◽

Surface Temperature ◽

North American ◽

Radiative Forcing ◽

Tropical Pacific ◽

Global Warming Hiatus ◽

Warming Hiatus ◽

The Impact ◽

The Tropical Pacific

Abstract Portions of western North America have experienced prolonged drought over the last decade. This drought has occurred at the same time as the global warming hiatus—a decadal period with little increase in global mean surface temperature. Climate models and observational analyses are used to clarify the dual role of recent tropical Pacific changes in driving both the global warming hiatus and North American drought. When observed tropical Pacific wind stress anomalies are inserted into coupled models, the simulations produce persistent negative sea surface temperature anomalies in the eastern tropical Pacific, a hiatus in global warming, and drought over North America driven by SST-induced atmospheric circulation anomalies. In the simulations herein the tropical wind anomalies account for 92% of the simulated North American drought during the recent decade, with 8% from anthropogenic radiative forcing changes. This suggests that anthropogenic radiative forcing is not the dominant driver of the current drought, unless the wind changes themselves are driven by anthropogenic radiative forcing. The anomalous tropical winds could also originate from coupled interactions in the tropical Pacific or from forcing outside the tropical Pacific. The model experiments suggest that if the tropical winds were to return to climatological conditions, then the recent tendency toward North American drought would diminish. Alternatively, if the anomalous tropical winds were to persist, then the impact on North American drought would continue; however, the impact of the enhanced Pacific easterlies on global temperature diminishes after a decade or two due to a surface reemergence of warmer water that was initially subducted into the ocean interior.

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Extreme North America Winter Storm Season of 2013/14: Roles of Radiative Forcing and the Global Warming Hiatus

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-15-00133.1 ◽

2015 ◽

Vol 96 (12) ◽

pp. S25-S28 ◽

Cited By ~ 12

Author(s):

Xiaosong Yang ◽

G. A. Vecchi ◽

T. L. Delworth ◽

K. Paffendorf ◽

L. Jia ◽

...

Keyword(s):

Global Warming ◽

North America ◽

Radiative Forcing ◽

Winter Storm ◽

Global Warming Hiatus ◽

Warming Hiatus ◽

Extreme North

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Global sensitivity analysis of the Indian monsoon during the Pleistocene

Climate of the Past ◽

10.5194/cp-11-45-2015 ◽

2015 ◽

Vol 11 (1) ◽

pp. 45-61 ◽

Cited By ~ 10

Author(s):

P. A. Araya-Melo ◽

M. Crucifix ◽

N. Bounceur

Keyword(s):

Sensitivity Analysis ◽

Surface Temperature ◽

Sea Surface Temperature ◽

Mixed Layer ◽

Global Sensitivity Analysis ◽

Indian Monsoon ◽

Mixed Layer Depth ◽

Sea Surface ◽

Layer Depth ◽

Global Sensitivity

Abstract. The sensitivity of the Indian monsoon to the full spectrum of climatic conditions experienced during the Pleistocene is estimated using the climate model HadCM3. The methodology follows a global sensitivity analysis based on the emulator approach of Oakley and O'Hagan (2004) implemented following a three-step strategy: (1) development of an experiment plan, designed to efficiently sample a five-dimensional input space spanning Pleistocene astronomical configurations (three parameters), CO2 concentration and a Northern Hemisphere glaciation index; (2) development, calibration and validation of an emulator of HadCM3 in order to estimate the response of the Indian monsoon over the full input space spanned by the experiment design; and (3) estimation and interpreting of sensitivity diagnostics, including sensitivity measures, in order to synthesise the relative importance of input factors on monsoon dynamics, estimate the phase of the monsoon intensity response with respect to that of insolation, and detect potential non-linear phenomena. By focusing on surface temperature, precipitation, mixed-layer depth and sea-surface temperature over the monsoon region during the summer season (June-July-August-September), we show that precession controls the response of four variables: continental temperature in phase with June to July insolation, high glaciation favouring a late-phase response, sea-surface temperature in phase with May insolation, continental precipitation in phase with July insolation, and mixed-layer depth in antiphase with the latter. CO2 variations control temperature variance with an amplitude similar to that of precession. The effect of glaciation is dominated by the albedo forcing, and its effect on precipitation competes with that of precession. Obliquity is a secondary effect, negligible on most variables except sea-surface temperature. It is also shown that orography forcing reduces the glacial cooling, and even has a positive effect on precipitation. As regards the general methodology, it is shown that the emulator provides a powerful approach, not only to express model sensitivity but also to estimate internal variability and detect anomalous simulations.

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Sea-surface CO<sub>2</sub> fugacity in the subpolar North Atlantic

Biogeosciences ◽

10.5194/bg-5-535-2008 ◽

2008 ◽

Vol 5 (2) ◽

pp. 535-547 ◽

Cited By ~ 42

Author(s):

A. Olsen ◽

K. R. Brown ◽

M. Chierici ◽

T. Johannessen ◽

C. Neill

Keyword(s):

North Atlantic ◽

Surface Waters ◽

Mixed Layer Depth ◽

Sea Surface ◽

First Year ◽

Layer Depth ◽

High Resolution Data ◽

Chl A ◽

Wide Range ◽

Summer Warming

Abstract. We present the first year-long subpolar trans-Atlantic set of surface seawater CO2 fugacity (fCO2sw) data. The data were obtained aboard the MV Nuka Arctica in 2005 and provide a quasi-continuous picture of the fCO2sw variability between Denmark and Greenland. Complementary real-time high-resolution data of surface chlorophyll-a (chl-a) concentrations and mixed layer depth (MLD) estimates have been collocated with the fCO2sw data. Off-shelf fCO2sw data exhibit a pronounced seasonal cycle. In winter, surface waters are saturated to slightly supersaturated over a wide range of temperatures. Through spring and summer, fCO2sw decreases by approximately 60 μatm, due to biological carbon consumption, which is not fully counteracted by the fCO2sw increase due to summer warming. The changes are synchronous with changes in chl-a concentrations and MLD, both of which are exponentially correlated with fCO2sw in off-shelf regions.

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