Changes In Heat Content Research Articles

Sea level and heat content changes in the western North Pacific

AbstractAltimetry‐observed sea level rise (SLR) over the western North Pacific (WNP), including the South China Sea, Yellow Sea, East China Sea, and East/Japan Sea, has a rate of ~5 mm/year over 1993–2010, which is about 1.5 times the rate of the global mean. Here we have examined sea level changes and related ocean heat content (OHC) in the WNP by comparing results from a non‐Boussinesq ocean general circulation model (mass‐conserved) with data sets from altimeters, the Gravity Recovery and Climate Experiment (GRACE), and in situ profiles. Our model reproduces the altimetry regional trends as well as their seasonal/interannual variations. Adding a GRACE‐estimated mass to the model result further explains the altimetry SLR in a way that mass‐induced effect contributes more in the midlatitudes than in the tropical WNP over the GRACE period. In addition, interannual variability and linear trend of regional sea levels are explained mainly by changes in the OHC due to heat convergence and divergence by ocean circulations, while seasonal variability is caused mainly by surface air‐sea fluxes. To understand the underline physics, a comparative experiment was carried out, showing that the recent strengthening trends of SLR and OHC in the tropical regions are significantly attributed to the heat and water mass redistribution in the upper ocean caused by the intensified easterly trade wind over the past two decades.

Air-sea and oceanic heat flux contributions to the heat budget of the northern Gulf of Alaska shelf

We constructed annual cycles of National Centers for Environmental Prediction air-sea fluxes and temporal oceanic heat content change from Seward Line hydrographic surveys to quantify the different contributions to the oceanic heat budget within the Alaska Coastal Current (ACC) on the northern Gulf of Alaska shelf. The deficit between air-sea fluxes and the temporal change in oceanic heat content throughout the cooling season (October–April) varies from ~40 to 110Wm�2 and is balanced by ocean heat flux convergence. Cross-shelf heat flux convergence is insignificant on annual average, and the nearshore heat budget is likely entirely balanced by the ACC, which resupplies ~15%–50% of the heat removed by air-sea fluxes during the cooling season. Furthermore, we estimated spatial heat flux gradients and conclude that air-sea fluxes increase from east to west and from offshore to onshore. The cross-shore gradients are governed by wind speed gradients, likely due to ageostrophic nearshore wind events during the cooling season, while the along-shelf heat flux gradients are governed by the occurrence of low-pressure systems in the northern GOA that result in cold northerly winds over the northwestern GOA. These results underline the ACC’s role as the dominant oceanic heat source to the northern GOA shelf and further imply an increased cooling rate of the ACC west of the Seward Line. Furthermore, our analysis showed that nearshore regions, particularly waters in the ACC, are subjected to stronger winter cooling than the middle and outer shelves.

The effect of progressive heat acclimation on change in body heat content in young males

Heat acclimation improves the physiological capacity to dissipate heat. As previous studies have only relied upon core temperature and local heat loss measurements, it remains unclear the extent to which whole‐body heat loss, and therefore body heat storage is altered during heat acclimation. Using direct calorimetry, we examined whole‐body heat exchange during progressive increases in the requirement for heat loss during and following a 14‐day heat acclimation protocol. Six young males (Mean±SD, age: 23±3yrs) performed intermittent exercise (3×30‐min bouts of cycling at 300, 350, and 400 W·m−2separated by 10 min rest period) in dry heat (35°C, 20% relative humidity [RH]) prior to (day 0), during (day 7), and at the end (day 14) of a 14‐day heat acclimation. On days 1–6 and 8–13, subjects cycled for 90 min (~50% VO2max) in the heat (40°C, 20% RH). Despite a similar requirement between test days, significantly lower increases in evaporative heat loss were observed for the final exercise bout in days 0 (P=0.01) and 7 (P=0.02) relative to day 14. After 7 days of acclimation, the ΔHb following the exercise did not significantly decrease from day 0 (673±165 vs. 449±109 kJ, p=0.112). However, on day 14 the ΔHb was significantly reduced compared to day 0 (363±64 vs. 673±165 kJ, p=0.04). These data suggest that 14 days is necessary to achieve sufficient heat acclimation to significantly reduce heat storage during exercise in the heat. Support: Deep Mining Research Consortium (Dr. Glen P. Kenny)

Study of seasonal variability and heat budget of the East Australian Current using two eddy-resolving ocean circulation models

Two mutually exclusive ocean models, Ocean general circulation model for the Earth Simulator (OFES) and the Bluelink ReANalysis (version 2.1; BRAN2.1), and the spin-up model (SPINUP4) of BRAN2.1 were used to investigate seasonal variability of the East Australian Current (EAC). These model outputs were tested against satellite and in situ data. The seasonally averaged sea surface temperature (SST) in the OFES and SPINUP4 shows a negative bias of 1 °C. However, the OFES, SPINUP4, and BRAN2.1 have a similar seasonal cycle in SST. The annual mean EAC transport computed at 28°S from the three models shows a good agreement with annual mean transport computed using the in situ data. However, they have considerable differences in terms of annual cycle. A better performance of the BRAN2.1 in simulating the temperature field is a result of data assimilation. The advection of heat across the open boundaries contributes ∼50 % of the heat content change in the region. This study suggests that the advection by the EAC plays a significant role in heat content change of the region.

Uncertainty in modeled upper ocean heat content change

This paper examines the uncertainty in the change in the heat content in the ocean component of a general circulation model. We describe the design and implementation of our statistical methodology. Using an ensemble of model runs and an emulator, we produce an estimate of the full probability distribution function (PDF) for the change in upper ocean heat in an Atmosphere/Ocean General Circulation Model, the Community Climate System Model v. 3, across a multi-dimensional input space. We show how the emulator of the GCM’s heat content change and hence, the PDF, can be validated and how implausible outcomes from the emulator can be identified when compared to observational estimates of the metric. In addition, the paper describes how the emulator outcomes and related uncertainty information might inform estimates of the same metric from a multi-model Coupled Model Intercomparison Project phase 3 ensemble. We illustrate how to (1) construct an ensemble based on experiment design methods, (2) construct and evaluate an emulator for a particular metric of a complex model, (3) validate the emulator using observational estimates and explore the input space with respect to implausible outcomes and (4) contribute to the understanding of uncertainties within a multi-model ensemble. Finally, we estimate the most likely value for heat content change and its uncertainty for the model, with respect to both observations and the uncertainty in the value for the input parameters.

Quasi-Lagrangian observations of the upper ocean response to wintertime forcing in the Gulf Stream

Records of velocity, temperature, conductivity, and pressure from drifting, profiling instruments acquired in the Gulf Stream region during February and March of 2007 as part of the CLIMODE program are used to examine change in upper ocean heat content. Two Electromagnetic Autonomous Profiling EXplorer (EM-APEX) floats and an Air–Sea Interaction buoy coupled with a Finescale Lagrangian Instrument System (ASIS/FILIS) were released separately in the Gulf Stream and profiled to depths of 550m as they drifted downstream. A mixed layer heat balance is estimated using the quasi-Lagrangian float records in combination with surface fluxes derived from a 0.25 degree resolution meteorological model. The advection term is estimated using observations of velocity relative to the floats and SeaSoar temperature surveys to obtain the temperature gradient across the Gulf Stream. Periods of large surface heat flux and wind stress were observed as winter storms carrying cold air passed over the warm Gulf Stream. In agreement with previous studies, it is found that advective terms associated with the large vertical shear of the Gulf Stream dominate the mixed layer heat balance following the floats. This conclusion is further supported by runs of the Price–Weller–Pinkel (PWP) mixed layer model used to examine the expected upper ocean evolution based on the surface heat fluxes.

Meridional movement of wind anomalies during ENSO events and their role in event termination

Observational analysis has shown that when El Niño‐Southern Oscillation (ENSO) events typically reach their peak amplitude in boreal winter, the associated zonal wind anomalies abruptly shift southward so that the maximum anomalous zonal wind is located around 5°–7°S. Here, an analysis utilizing multiple wind products identifies a clear ENSO phase nonlinearity in the extent of this meridional wind movement and its dynamically linked changes in equatorial heat content. It is shown that the meridional wind movement and its discharging effect increase with increasing El Niño amplitude, while both remain relatively small regardless of La Niña amplitude. This result implies that asymmetries in the extent of the meridional wind shift may contribute to the observed asymmetry in the duration of El Niño and La Niña events. We also evaluate the result sensitivities to wind product selection and discuss Eastern Pacific (EP) and Central Pacific (CP) El Niño event differences.

Variability of Coastal and Ocean Water Temperature in the Upper 700 m along the Western Iberian Peninsula from 1975 to 2006

Temperature is observed to have different trends at coastal and ocean locations along the western Iberian Peninsula from 1975 to 2006, which corresponds to the last warming period in the area under study. The analysis was carried out by means of the Simple Ocean Data Assimilation (SODA). Reanalysis data are available at monthly scale with a horizontal resolution of 0.5°×0.5° and a vertical resolution of 40 levels, which allows obtaining information beneath the sea surface. Only the first 21 vertical levels (from 5.0 m to 729.35 m) were considered here, since the most important changes in heat content observed for the world ocean during the last decades, correspond to the upper 700 m. Warming was observed to be considerably higher at ocean locations than at coastal ones. Ocean warming ranged from values on the order of 0.3°C dec−1 near surface to less than 0.1°C dec−1 at 500 m, while coastal warming showed values close to 0.2°C dec−1 near surface, decreasing rapidly below 0.1°C dec−1 for depths on the order of 50 m. The heat content anomaly for the upper 700 m, showed a sharp increase from coast (0.46 Wm−2) to ocean (1.59 Wm−2). The difference between coastal and ocean values was related to the presence of coastal upwelling, which partially inhibits the warming from surface of near shore water.

Water column conditions in a coastal lagoon near Jeddah, Red Sea

Water column conditions in a lagoon near Jeddah are investigated on the basis of changes in potential energy. Three major factors including balance of surface heat at the air-sea interface, wind and tidal mixing are considered. A negative potential energy change dvdt will develop stratification, whereas positive dvdt will tend to mix the water column. The tidal effect is greater in summer with wind mixing showing no great variations. The buoyancy effect of the heat balance at the surface is negative from April to October. This negative buoyancy effect will tend to develop stratification but the positive contributions of wind and tide counteract this and the water column remains mixed except in September and October, when a weak stratification may develop. Generally, the water column remains practically mixed throughout the year. The change in heat content of the water column from mid-April to mid-September is about 3.3×108J. During this period the net heat input at the air interface is about 2.0×108J, which is about 40% less than the heat content of the water column, showing that the heat is advected towards the central area from the shallower periphery of the lagoon.

전지구 수온 및 염분 자료 품질 관리에 관한 논의

성공적인 국제 Argo 사업을 통해 얻어진 고해상도의 수온 및 염분 프로파일들을 이용하여 준실시간으로 3차원 전지구 해양 상태의 재현이 가능해졌으며, 전지구 해양 자료 분석 연구에 대한 관심 또한 크게 증가하였다. 본 연구에서는 XBT와 Argo 자료의 계통 오차, 열염분 해수면 높이 및 인공위성 관측 자료와의 해수면 수지 불일치, 해양 열용량 변동 및 객관 분석장 개발 현황 등 최근의 자료 분석 연구의 주요 쟁점들에 관해 정리하였다. 특히 동아시아 해역에서의 지역 규모 해양 기후 변화 분석에 앞서 매우 신중한 해양 자료의 품질 관리 및 전구 규모의 해양 변동에 관한 이해가 필요하다는 것을 강조하였다. High-density temperature and salinity profiles from the successful international Argo project made it possible to reproduce the three-dimensional global ocean state in near-real time, which also increased much attention on the data analysis studies of global ocean. This paper reviewed several important issues on the recent data analysis studies such as systematic biases of XBT (eXpendable BathyThermograph) and Argo data, sea level budget discrepancy between steric height and satellite observed data, heat content change, and the current status of the development of objective analysis fields. This study also emphasized that it is required to carry out very cautious ocean data quality control and understand global-scale ocean variability prior to analyzing the regional-scale ocean climate change, particularly, in the East Asian marginal Seas.

A Decadal Prediction Case Study: Late Twentieth-Century North Atlantic Ocean Heat Content

Abstract An ensemble of initialized decadal prediction (DP) experiments using the Community Climate System Model, version 4 (CCSM4) shows considerable skill at forecasting changes in North Atlantic upper-ocean heat content and surface temperature up to a decade in advance. Coupled model ensembles were integrated forward from each of 10 different start dates spanning from 1961 to 2006 with ocean and sea ice initial conditions obtained from a forced historical experiment, a Coordinated Ocean-Ice Reference Experiment with Interannual forcing (CORE-IA), which exhibits good correspondence with late twentieth-century ocean observations from the North Atlantic subpolar gyre (SPG) region. North Atlantic heat content anomalies from the DP ensemble correlate highly with those from the CORE-IA simulation after correcting for a drift bias. In particular, the observed large, rapid rise in SPG heat content in the mid-1990s is successfully predicted in the ensemble initialized in January of 1991. A budget of SPG heat content from the CORE-IA experiment sheds light on the origins of the 1990s regime shift, and it demonstrates the extent to which low-frequency changes in ocean heat advection related to the Atlantic meridional overturning circulation dominate temperature tendencies in this region. Similar budgets from the DP ensembles reveal varying degrees of predictive skill in the individual heat budget terms, with large advective heat flux anomalies from the south exhibiting the highest correlation with CORE-IA. The skill of the DP in this region is thus tied to correct initialization of ocean circulation anomalies, while external forcing is found to contribute negligibly (and for incorrect reasons) to predictive skill in this region over this time period.

Body heat storage during intermittent work in hot–dry and warm–wet environments

We examined heat balance using an American Conference of Governmental Industrial Hygienists threshold limit value allocated exercise protocol in hot-dry (HD; 46 °C, 10% relative humidity (RH)) and warm-wet (WW; 33 °C, 60% RH) environments of equivalent WBGT (29 °C) for different clothing ensembles. Whole-body heat exchange and changes in body heat content (ΔH(b)) were measured using simultaneous direct whole-body and indirect calorimetry. Eight males performed six 15-min cycling periods at a constant rate of metabolic heat production (360 W) interspersed by 5-min rest periods for six experimental trials: HD and WW environments for a seminude control (CON), modified work uniform (MWU, moisture permeable top and work pants), and standard work uniform (SWU, work coveralls and cotton undergarments). Whole-body evaporative and dry heat exchange, rectal temperature (T(re)), and heart rate were measured continuously. The cumulative ΔH(b) during the 2 h intermittent exercise protocol was similar between HD and WW environments for each of the clothing ensembles (CON, 387 ± 55 vs. 435 ± 49 kJ; MWU, 485 ± 58 vs. 531 ± 61 kJ; SWU, 585 ± 74 vs. 660 ± 54 kJ, respectively). Similarly, no differences in T(re) (CON, 37.67 ± 0.07 vs. 37.48 ± 0.08 °C; MWU, 37.73 ± 0.08 vs. 37.53 ± 0.09 °C; SWU, 38.01 ± 0.09 vs. 37.94 ± 0.05 °C) or heat rate (CON, 93 ± 3 vs. 84 ± 3 beats·min⁻¹; MWU, 102 ± 5 vs. 95 ± 9 beats·min⁻¹; SWU, 119 ± 8 vs. 110 ± 9 beats·min⁻¹) were observed at the end of the 2 h intermittent exercise protocol in HD vs. WW environments, respectively. We showed similar levels of thermal and cardiovascular strain for intermittent work performed in high heat stress conditions of varying environmental conditions but similar WBGT.

World ocean heat content and thermosteric sea level change (0–2000 m), 1955–2010

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−1 for 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.

On the North Atlantic Ocean Heat Content Change between 1955–70 and 1980–95

Abstract The upper-ocean heat content of the North Atlantic has undergone significant changes over the last 50 years but the underlying physical mechanisms are not yet well understood. In the present study, the authors examine the North Atlantic ocean heat content change in the upper 700 m between the 1955–70 and 1980–95 periods. Consistent with previous studies, the large-scale pattern consists of warming of the tropics and subtropics and cooling of the subpolar ocean. However, this study finds that the most significant heat content change in the North Atlantic during these two time periods is the warming of the Gulf Stream region. Numerical experiments strongly suggest that this warming in the Gulf Stream region is largely driven by changes of the large-scale wind forcing. Furthermore, the increased ocean heat content in the Gulf Stream region appears to feedback on to the atmosphere, resulting in warmer surface air temperature and enhanced precipitation there.

Changes in Atlantic water properties: an important factor in the European Arctic marine climate

Abstract Walczowski, W., Piechura, J., Goszczko, I., and Wieczorek, P. 2012. Changes in Atlantic water properties: an important factor in the European Arctic marine climate. – ICES Journal of Marine Science, 69: 864–869. The advection of warm Atlantic water (AW) through the Nordic Seas and its transformation (cooling and freshening) is one of the most important climatological processes in the region. Time-series of hydrographic observations in the northern Nordic Seas and the Fram Strait region are presented and analysed. Significant variability in the properties of AW has been observed in recent years. A 15-year time-series of summer observations indicate positive trends in salinity and temperature and two 5–6-year cycles. The northward advance of AW in 2006 was an unprecedented event. The position of the warm-water tongue shifted more than 350 km to the north, and temperatures in the West Spitsbergen Current reached the highest values ever recorded. These changes in AW temperature, heat content, and northward transport had a strong influence on the oceanic climate and sea-ice conditions north of Svalbard. These oceanic signals led to environmental changes that confirm the primary role of the ocean in shaping the climate of the region.

East–west asymmetry in surface mixed layer and ocean heat content in the Pacific sector of the Arctic Ocean derived from AMSR-E sea surface temperature

Deep (greater than 25m) and anomalously warm surface mixed layer (SML) has been evident in the Pacific sector of the Arctic Ocean since 2007. This warm SML contributes to the formation of maximum near surface temperature, which act as the sea-ice formation “inhibitor”, after freeze-up season. In this study, we attempt to estimate the ocean heat content (OHC) in the SML of the Pacific sector of the Arctic Ocean. The surface mixed layer depth (SMLD) and OHC from 2007 to 2010 were estimated from SST measured by the microwave radiometer AMSR-E and NCEP-derived net heat budget, based on the assumption that changes of heat content within SML can be explained by the air–sea heat exchange only.Estimated SMLD and OHC were well comparable with the in-situ CTD measurements, especially, in the western Canada Basin. SMLD greater than 25m (up to 40m) and OHC greater than 300MJ were estimated at southern Northwind Ridge area (73–75°N, 168–150°W), where the catastrophic reduction of sea ice has been reported, while less OHC was estimated at the eastern side of the Canada Basin. Although anomalous high SST has uniformly been captured over the northern Chukchi Sea and the Northwind Ridge area since 2007, our results indicate the nonuniformity of surface OHC distribution in the Canada Basin with relatively large amount in the Northwind Ridge area. Conversely, we can assume that the Northwind Ridge area is the plausible candidate for the Near Surface Temperature Maximum formation area. Recent thin ice condition is probably responsible for deepening SMLD, efficient ocean heat uptake, and delayed onset of sea ice formation in the Pacific sector of the Arctic Ocean. Our results also indicate oceanic horizontal or vertical heat flux along the sea ice edge, which will promote the suppression of sea ice growth during freeze-up season.

Quantifying heat balance components in neonates nursed under radiant warmers in neonatal intensive care

Neonatal intensive care units use radiant warmers (RW) to maintain stable body temperatures in many newborns. This study examined whether the rate of radiant heat required for heat balance (Rreq) is equal to the rate of radiant heat provided by the RW (Rprov). A systematic evaluation of time‐dependent changes in heat balance components was conducted in 10 newborns (mass: 2829±636 g; age: 9.2±11.0 days; BSA: 0.19±0.03 m2) nursed under RW. Metabolic rate, evaporative heat loss, convective and conductive heat flow, rectal temperature (Trec) and mean skin temperature (Tsk) were measured continuously for 105 min. The rate of body heat storage (S) was calculated using a two‐compartment model of ‘core’ (Trec) and ‘shell’ (Tsk) temperatures. Mean Rprov (1.28±2.59 W) and Rreq (1.25±2.51W) were not significantly different (P=0.63). However, while the resultant mean change in body heat content after 105 min was low (+0.46±2.79 kJ) and not significantly different from zero (P>0.05), an acute time‐dependent change in body heat storage was evidenced by a mean positive heat storage component of +6.64±2.98 kJ and a mean negative heat storage component of −6.17±2.64 kJ. Accordingly, the mean difference between maximum and minimum values for Trec and Tskwere 0.71±0.37°C and 2.18±0.81°C respectively. In conclusion, while RW maintain astable core temperature over a prolonged period, they induce acute bouts of heat imbalance.Supported by a NSERC Discovery Grant (O. Jay) & a CHEO Dept. of Surgery Research Grant (S. Chou).

Cortisol and Interleukin-6 Responses During Intermittent Exercise in Two Different Hot Environments with Equivalent WBGT

Blood marker concentrations such as cortisol (COR) and interleukin (IL)-6 are commonly used to evaluate the physiological strain associated with work in the heat. It is unclear, however, if hot environments of an equivalent thermal stress, as defined by a similar wet bulb globe temperature (WBGT), result in similar response patterns. This study examined markers of neuroendocrine (COR) and immune (IL-6) responses, as well as the cardiovascular and thermal responses, relative to changes in body heat content measured by whole-body direct calorimetry during work in two different hot environments with equivalent WBGT. Eight males performed a 2-hr heavy intermittent exercise protocol (six 15-min bouts of cycling at a constant rate of metabolic heat production (360W) interspersed by 5-min rest periods) in Hot/Dry (46°C, 10% relative humidity [RH]) and Warm/Humid (33°C, 60% RH) conditions (WBGT ∼ 29°C). Whole-body evaporative and dry heat exchange, change in body heat content (ΔHb), rectal temperature (Tre), and heart rate were measured continuously. Venous blood was obtained at rest (PRE) and the end of each exercise bout for the measurement of changes in plasma volume (PV), plasma protein (an estimate of plasma water changes), COR, and IL-6. Ratings of perceived exertion and thermal sensation were measured during the last minute of each exercise bout. No differences existed for ΔHb, heart rate, Tre,%ΔPV, plasma protein concentration, perceptual strain (thermal sensation, perceived exertion), and COR between the Hot/Dry and Warm/Humid conditions. IL-6 exhibited an interaction effect (p = 0.041), such that greater increases were observed in the Hot/Dry (Δ = 1.61 pg·mL−1) compared with the Warm/Humid (Δ = 0.64 pg·mL−1) environment. These findings indicate that work performed in two different hot environments with equivalent WBGT resulted in similar levels of thermal, cardiovascular, and perceptual strain, which support the use of the WBGT stress index. However, the greater IL-6 response in the Hot/Dry requires further research to elucidate the effects of different hot environments and work intensities.

Oceanic and terrestrial biospheric CO2 uptake estimated from atmospheric potential oxygen observed at Ny-Ålesund, Svalbard, and Syowa, Antarctica

ABSTRACTSimultaneous measurements of the atmospheric O2/N2 ratio and CO2 concentration were made at Ny-Ålesund, Svalbard, and Syowa, Antarctica for the period 2001–2009. Based on these measurements, the observed atmospheric potential oxygen (APO) values were calculated. The APO variations produced by changes in the oceanic heat content were estimated using an atmospheric transport model and heat-driven air–sea O2 (N2) fluxes, and then subtracted from observed interannual variations of APO. The oceanic CO2 uptake derived from the resulting ‘corrected’ secular trend of APO showed interannual variability of less than ±0.6 GtC yr−1, significantly smaller than that derived from the ‘uncorrected’ trend of APO (±0.9 GtC yr−1). The average CO2 uptake during the period 2001–2009 was estimated to be 2.9±0.7 and 0.8±0.9 GtC yr−1 for the ocean and terrestrial biosphere, respectively. By excluding the influence of El Niño around 2002–2003, the terrestrial biospheric CO2 uptake for the period 2004–2009 increased to 1.5±0.9 GtC yr−1, while the oceanic uptake decreased slightly to 2.8±0.8 GtC yr−1.

Turbulent and Transitional Modeling of Drag on Oceanographic Measurement Devices

Computational fluid dynamic techniques have been applied to the determination of drag on oceanographic devices (expendable bathythermographs). Such devices, which are used to monitor changes in ocean heat content, provide information that is dependent on their drag coefficient. Inaccuracies in drag calculations can impact the estimation of ocean heating associated with global warming. Traditionally, ocean-heating information was based on experimental correlations which related the depth of the device to the fall time. The relation of time-depth is provided by a fall-rate equation (FRE). It is known that FRE depths are reasonably accurate for ocean environments that match the experiments from which the correlations were developed. For other situations, use of the FRE may lead to depth errors that preclude XBTs as accurate oceanographic devices. Here, a CFD approach has been taken which provides drag coefficients that are used to predict depths independent of an FRE.