Drop In Surface Temperature Research Articles

The use of thermal imaging to evaluate body temperature changes of athletes during training and a study on the impact of physiological and morphological factors on skin temperature

PurposeThe aim of this study was to assess the temperature changes of selected body surfaces (the arm and forearm) as a response to 90-minute physical exercise as well as to analyze the impact of physiological and morphological factors on the dynamics of temperature change.MethodsA study group that consisted of 12 professional volleyball players was subjected to endurance training which lasted 90 minutes. Numerous physiological and morphological factors were measured, with mean temperatures registered from the body surface of the upper extremities before, immediately after, and ten min after physical effort by a thermal camera (SC500 ThermaCAM camera) at room temperature.ResultsAfter physical exercise, a fall in skin temperature resulting from prolonged sweating during the dynamic exercise tests was observed. The temperature changes in volleyball players, recorded in a series of tests, were found to be larger on the front surfaces of their upper extremities when compared to the rear. In addition, statistically significant positive correlation between maximum oxygen uptake (VO<sub>2max</sub>) and %HR<sub>max</sub>, calculated with the decrease in skin temperatures, was found.ConclusionsThe strong and statistically significant influence of maximum oxygen uptake on the drop in surface temperature of the upper extremities (arm and forearm) immediately after the exercise indicates that thermography can be used as an additional, non-invasive method that provides information on a player's fitness level in comparison to other athletes.

Damage analysis of an RC column subjected to long-term transient elevated temperature

Damage in a reinforced concrete column subjected to long-term elevated temperature (approximately 150°C) was studied by conducting detail inspection as well as finite element analysis. The damage information was collected through visual inspection, non-destructive tests, coring, and chemical analysis. Inspection results illustrated more damage level in the portion exposed to high temperature. Chemical analysis as well as cracking patterns indicated that the damage was not the same as the damage caused by fire attack and was not caused by chloride penetration, carbonation or sulphate attack. The mechanism of the damage was clarified by using finite element analysis with a condition of sudden drop of surface temperature. It was found from the analysis that cracking can be induced on the surface of the column due to temperature gradient if there is a substantial surface temperature drop.

Pliocene Indonesian Throughflow and Leeuwin Current dynamics: Implications for Indian Ocean polar heat flux

To understand the gradual global cooling during the mid‐Pliocene (3.5–2.5 Myr ago) one needs to consider the tectonical constriction of tropical seaways, which affected ocean circulation and the evolution of climate. Here we use paired measurements of δ18O and Mg/Ca ratios of planktonic foraminifera to reconstruct the Pliocene hydrography of the western tropical Indian Ocean (Site 709C) and changes in the Leeuwin Current in the eastern subtropical Indian Ocean (Site 763A) in response to Indonesian Gateway dynamics. Today, the Indonesian Throughflow (ITF) and, subsequently, the warm southward flowing Leeuwin Current off Western Australia are essential for the polar heat transport in the Indian Ocean. During 3.5–3 Ma, sea surface temperatures significantly dropped in the Leeuwin Current area, becoming since ∼3.3 Ma 2°C–3°C cooler than the rather unchanged sea surface temperatures from the eastern and western tropical Indian Ocean. We refer this drop in sea surface temperatures to a weakened Leeuwin Current with severe climatic effects on Western Australia induced by a tectonically reduced surface ITF. We suggest that this reduced surface ITF led to a diminished poleward heat transport in the Indian Ocean resulting in a weakened Leeuwin Current and possibly to cooling of the Benguela upwelling system.

Examining the Effects of Dust Aerosols on Satellite Sea Surface Temperatures in the Mediterranean Sea Using the Medspiration Matchup Database

Abstract Dust aerosol plumes from the Sahara cover the Mediterranean Sea regularly during the summer months (June–August) and occasionally during other seasons. Dust can absorb infrared longwave radiation, thus causing a drop in sea surface temperature (SST) retrievals from satellite. To quantify the magnitude of this absorption and to understand the sources of the biases that might be introduced when trying to validate SST algorithms with in situ bulk temperatures, the effects of the dust absorption are studied using the Medspiration Match-up Database. This database provides in situ and satellite SSTs derived from the Advanced Very High Resolution Radiometer (AVHRR) and the Advanced Along-Track Scanning Radiometer (AATSR), and the difference between skin and bulk measurements is calculated in order to obtain errors or residuals, which are classified by ranges and compared to an aerosol optical thickness product derived from the sensors. The behavior of the residuals is studied and there is clear correspondence between higher residual values and higher aerosol concentrations, though in some cases this relation is not so evident, especially during autumn months. Residuals for this period are then related to other atmospheric effects and layer boundary physical processes by using ancillary data (e.g., soundings).

Typhoon Kai-Tak: An Ocean’s Perfect Storm

Abstract An unusually intense sea surface temperature drop (ΔSST) of about 10.8°C induced by the Typhoon Kai-Tak is observed in the northern South China Sea (SCS) in July 2000. Observational and high-resolution SCS model analyses were carried out to study the favorable conditions and relevant physical processes that cause the intense surface cooling by Kai-Tak. Upwelling and entrainment induced by Kai-Tak account for 62% and 31% of the ΔSST, respectively, so that upwelling dominates vertical entrainment in producing the surface cooling for a subcritical storm such as Kai-Tak. However, wind intensity and propagation speed alone cannot account for the large ΔSST. Prior to Kai-Tak, the sea surface was anomalously warm and the main thermocline was anomalously shallow. The cause was a delayed transition of winter to summer monsoon in the northern SCS in May 2000. This produced an anomalously strong wind stress curl and a cold eddy capped by a thin layer of very warm surface water west of Luzon. Kai-Tak was the ocean’s perfect storm in passing over the eddy at the “right time,” producing the record SST drop and high chlorophyll-a concentration.

3차원 PIV를 활용한 초음파 진동에 의해 발생된 음향 유동을 이용한 스마트 냉각법 연구

In order to analyze the quantitative characteristics of acoustic streaming, experimental setup of 3-D stereoscopic PIV(particle imaging velocimetry) was designed and quantitative ultrasonic flow fields in the gap between the ultrasonic vibrator and heat source were measured. Utilizing acoustic streaming induced by ultrasonic vibration, surface temperature drop of cooling object was also measured. The study on smart cooling method by acoustic streaming induced by ultrasonic vibration was performed due to the empirical relations of flow pattern, average flow velocity, different gaps, and enhancement on cooling rates in the gap. Average velocity fields and maximum acoustic streaming velocity in the open gap between the stationary cylindrical heat source and ultrasonic vibrator were experimentally measured at no vibration, resonance, and non-resonance. It was clearly observed that the enhancement of cooling rates existed owing to the acoustic air flow in the gap at resonance and non-resonance induced by ultrasonic vibration. The ultrasonic wave propagating into air in the gap creates steady-state secondary eddy called acoustic streaming which enhances heat transfer from the heat source to encompassing air. The intensity of the acoustic streaming induced by ultrasonic vibration experimentally depended upon the gap between the heat source and ultrasonic vibrator. The ultrasonic vibration at resonance caused the increase of the acoustic streaming velocity and convective heat transfer augmentation when the flow fields by 3D stereoscopic PIV and temperature drop of the heat source were measured experimentally. The acoustic streaming velocity of air enhancement on cooling rates in the gap is maximal when the gap agrees with the multiples of half wavelength of the ultrasonic wave, which is specifically 12 mm.

An abrupt drop in Northern Hemisphere sea surface temperature around 1970

The twentieth-century trend in global-mean surface temperature was not monotonic: temperatures rose from the start of the century to the 1940s, fell slightly during the middle part of the century, and rose rapidly from the mid-1970s onwards. The warming-cooling-warming pattern of twentieth-century temperatures is typically interpreted as the superposition of long-term warming due to increasing greenhouse gases and either cooling due to a mid-twentieth century increase of sulphate aerosols in the troposphere, or changes in the climate of the world's oceans that evolve over decades (oscillatory multidecadal variability). Loadings of sulphate aerosol in the troposphere are thought to have had a particularly important role in the differences in temperature trends between the Northern and Southern hemispheres during the decades following the Second World War. Here we show that the hemispheric differences in temperature trends in the middle of the twentieth century stem largely from a rapid drop in Northern Hemisphere sea surface temperatures of about 0.3 °C between about 1968 and 1972. The timescale of the drop is shorter than that associated with either tropospheric aerosol loadings or previous characterizations of oscillatory multidecadal variability. The drop is evident in all available historical sea surface temperature data sets, is not traceable to changes in the attendant metadata, and is not linked to any known biases in surface temperature measurements. The drop is not concentrated in any discrete region of the Northern Hemisphere oceans, but its amplitude is largest over the northern North Atlantic.

The effects and characteristics of atmospheric dust during martian global dust storm 2001A

We present retrieved trends in dust optical depth, dust effective radius and surface temperature from our analysis of Mars Global Surveyor Thermal Emission Spectrometer daytime data from global dust storm 2001A, and describe their significance for the martian dust cycle. The dust optical depth becomes correlated with surface pressure during southern spring and summer in years both with and without a global dust storm, indicating that global dust mixing processes are important at those seasons. The correlation is low at other times of the year. We found that the observed decay of optical depths at the later stages of the dust storm match, to first-order, theoretical values of clearing from Stokes–Cunningham fallout of the dust. Zonally averaged effective radius is constant within standard deviation of results (between 1.2 and 2.0 μm, with a global mean for all seasons of 1.7 μm), at all latitudes and seasons except at southern latitudes of 35° and higher around equinoxes in both martian years, where it is larger than average (2–3 μm). The emergence and disappearance of these larger particles correlates with observations of polar cap edge storms at those latitudes. Northern latitude observations under similar conditions did not yield a similar trend of larger average effective radii during the equinoxes. We also report on a linear correlation between daytime surface temperature drop and rise in optical depth during the global dust storm. Global dust storm 2001A produced a significant optical depth and surface temperature change.

Dynamic features of successive upwelling events in the Baltic Sea - a numerical case study

Coastal upwelling often reveals itself during the thermal stratification season as an abrupt sea surface temperature (SST) drop. Its intensity depends not only on the magnitude of an upwelling-favourable wind impulse but also on the temperature stratification of the water column during the initial stage of the event. When a chain of upwelling events is taking place, one event may play a part in forming the initial stratification for the next one; consequently, SST may drop significantly even with a reduced wind impulse. Two upwelling events were simulated on the Polish coast in August 1996 using a three-dimensional, baroclinic prognostic model. The model results proved to be in good agreement with in situ observations and satellite data. Comparison of the simulated upwelling events show that the first one required a wind impulse of 28000 kg m-1 s-1 to reach its mature, full form, whereas an impulse of only 7500 kg m-1 s-1 was sufficient to bring about a significant drop in SST at the end of the second event. In practical applications like operational modelling, the initial stratification conditions prior to an upwelling event should be described with care in order to be able to simulate the coming event with very good accuracy.

High Temperature Fatigue of SPF Die Ni-Cr-Fe Heat Resistant Nickel-Chromium Cast Steels

Superplastic forming of titanium alloy sheets requests long time operating conditions in the range of 900-950°C. Moreover, in a classical press-furnace process environment, die surface temperature drops during sheet unloading and induces high temperature thermo-mechanical fatigue. In order to withstand such extreme conditions in oxidative atmosphere, cast heat resistant nickel chromium steel grades have been developed. The high chromium content (close to 25%) aims to protect against the oxidizing environment, whereas the nickel content is selected with respect to the expected in service loads. The 50% nickel grades are in general used for heating plates, huge casings and cover-plates; whereas 40% nickel grades are selected for inserts and medium size self-standing dies. Cost considerations (Nickel and machining) are also taken into account by the end users for making their choice. An extensive testing program has been performed, in the range of 20 to 950°C, to understand the high temperature fatigue behaviour of these grades and to identify material behaviour models for simulation purposes. This paper presents the major results of these research works and highlights the impact of the nickel content in terms of stress level and life time. Nevertheless, when looking on behaviour, test results show that a unified elasto-visco-plastic cyclic behaviour model is well suited for thermo-mechanical cyclic modelling whatever the grade is. Isothermal identification strategy and out of phase SPF die representative anisothermal fatigue validation are presented.

Dust emission and transport associated with a Saharan depression: February 2007 case

The dust activity over North Africa associated with the Saharan depression event in February 2007 is investigated by mean of spaceborne observations, ground‐based measurements, and mesoscale simulation with Meso‐NH. The main characteristics of the cyclone as well as the meteorological conditions during this event are described using the European Centre for Medium‐Range Weather Forecasts (ECMWF). The dust storm and cloud cover over North Africa is thoroughly described combining for the first time Spinning Enhanced Visible and Infra‐Red Imager (SEVIRI) images for the spatiotemporal evolution and Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and CloudSat observations for the vertical distribution. The Saharan depression formed over Algeria in the lee of the Atlas Mountains on the afternoon of 20 February in response to midlatitude trough intrusion. It migrated eastward with a speed of 11 m s−1 and reached Libya on 22 February before exiting the African continent toward the Mediterranean Sea on 23 February. The horizontal scale of the cyclone at the surface varied between 800 and 1000 km during its lifetime. On the vertical the cyclone extended over 8 km, and a potential vorticity of 2 potential vorticity units (PVU) was reported at its center at 3 km in altitude. The cyclone was characterized by a surface pressure anomaly of about 9 hPa with respect to the environment, a warm front typified at the surface by an increase in surface temperature of 5°C, and a sharp cold front characterized by a drop in surface temperature of 8°C and an increase in 10 m wind speed of 15 m s−1. The cyclone provided dynamical forcing that led to strong near‐surface winds and produced a major dust storm over North Africa. The dust was transported all around the cyclone leaving a clear eye at its center and was accompanied by a deep cloud band along the northwestern edge of the cyclone. On the vertical, slanted dust layers were consistently observed during the event over North Africa. Furthermore, the dust was lofted to altitudes as high as 7 km, becoming subject to long‐range transport. The model was able to reasonably reproduce the structure, lifetime, and trajectory of the cyclone. Also, comparison with Moderate Resolution Imaging Spectrometer (MODIS) deep blue aerosol optical depths and CALIPSO‐CloudSat observations suggests that the model can be reliably used to quantify the dust emissions associated with this event. The mean daily dust loads over the area influenced by the cyclone were simulated to range between 2 and 8 Tg during the lifetime of the Sharav cyclone (i.e., 5 days). This study suggests that dust emissions linked with Saharan cyclones may contribute significantly to the total dust load over West and North Africa observed annually.

Modeled Oceanic Response and Sea Surface Cooling to Typhoon Kai-Tak

An ocean response to typhoon Kai-Tak is simulated using an accurate fourth-order, basin-scale ocean model. The surface winds of typhoon Kai-Tak were obtained from QuikSCAT satellite images blended with the ECMWF wind fields. An intense nonlinear mesoscale eddy is generated in the northeast South China Sea (SCS) with a Rossby number of O (1) and on a 50-100 km horizontal scale. Inertial oscillation is clearly observed. Advection dominates as a strong wind shear drives the mixed layer flows outward, away from the typhoon center, thus forcing upwelling from deep levels with a high upwelling velocity (＞ 30m day^(-1)). A drop in sea surface temperature (SST) of more than 9℃ is found in both observation and simulation. We attribute this significant SST drop to the influence of the slow moving typhoon, initial stratification and bathymetry-induced upwelling in the northeast of the SCS where the typhoon hovered.

The responses of East Asian Summer monsoon to the North Atlantic Meridional Overturning Circulation in an enhanced freshwater input simulation

We investigated the response of the East Asian Summer Monsoon (EASM) to a weakened Atlantic Meridional Overturning Circulation (AMOC) and its mechanism in an enhanced freshwater input experiment (FW) by using a fully-coupled climate model. The response was a weakened EASM and the mechanisms can be explained as follows. The simulated weakened AMOC resulted in a drop in sea surface temperature (SST) in the North Atlantic (NA) and, correspondingly, an anomalous high sea level pressure (SLP) over the North American regions, which in turn increased the northeast surface winds across the equator in the eastern tropical Pacific (ETP). The anomalous northeast winds then induced further upwelling in the ETP and stronger air/sea heat exchange, therefore leading to an anomalous cooling of the eastern tropical sea surface. As a result, the climatologic Hadley Circulation (HC) was weakened due to an anomalous stronger sinking of air in the ETP north of the equator, whereas the Walker Circulation (WC) in the western tropical Pacific (WTP) north of the equator was strengthened with an eastward-shifted upwelling branch. This feature was in agreement with the anomalous convergent winds in the WTP, and led to a weakened EASM and less East Asian summer precipitation (EASP). Furthermore, comparison with previous freshwater experiments indicates that the strength of EASP could be influenced by the magnitude of the added freshwater.

Why a Large Amount of Rain Falls over the Sea in the Vicinity of Western Sumatra Island during Nighttime

Abstract Precipitation measurements from the Tropical Rainfall Measuring Mission satellite indicate that annual rainfall over the sea in the vicinity of western Sumatra Island is among the highest on the earth, and most of this rainfall occurs during nighttime. Surface meteorological observations at Tabing on the western coast of the island show frequent occurrences of sudden offshore winds accompanied by an abrupt drop in surface temperatures in the late afternoon and evening. Model simulations for a 1-month period during the rainy season of the region successfully simulate the satellite-observed regional distribution and diurnal variation of rainfall. The simulation results show that convection develops across a wide area over the mountainous areas of the island at similar times in the afternoon with the development of thermally induced local circulations. At these times of the day, convection over the sea along the western coast of the island is suppressed by the thermally and topographically induced diurnal changes in the boundary layer flow. When convection over the mountains of the island dissipates in the late afternoon and evening, a zone of cold surface outflow along the western coast results from the mountain convection breaking out to the sea. Meanwhile, the convective inhibition offshore is reduced in the evening, and the offshore flow causes regular occurrences of convection over the sea near the coast. The triggered convective systems propagate offshore and westward in multicell cluster storms during nighttime, bringing heavy rainfall over the sea off the western coast of the island. Sensitivity experiments with a flat-topography model demonstrate that the frequent occurrence of offshore flow in the late afternoon and evening on the western coast is caused by the mountainous topography of the island and its induced afternoon convection. The mountains on the island and the resultant thermally and convectively induced local circulations can play an important role in the formation of nocturnal abundant rainfall over the sea west of Sumatra Island.

A new stage 3 millennial climatic variability record from a SW France speleothem

We present a new high resolution speleothem stable isotope record from the Villars Cave (SW-France) that covers part of marine isotope stage (MIS) 3. The Vil14 stalagmite grew between ~ 52 and 29 ka. The δ 13C profile is used as a palaeoclimate proxy and clearly shows the interstadial substages 13, 12 and 11. The new results complement and corroborate previously published stalagmite records Vil9 and Vil27 from the same site. The Vil14 stalagmite chronology is based on 12 Th-U dating by MC-ICP-MS and 3 by TIMS. A correction for detrital contamination was done using the 230Th/ 232Th activity ratio measured on clay collected in Villars Cave. The Vil14 results reveal that the onset of Dansgaard–Oeschger (DO) events 13 and 12 occurred at ~ 49.8 ka and ~ 47.8 ka, respectively. Within uncertainties, this is coherent with the latest NorthGRIP time scale (GICC05-60 ka) and with speleothem records from Central Alps. Our data show an abrupt δ 13C increase at the end of DO events 14 to 12 which coincides with a petrographical discontinuity probably due to a rapid cooling. As observed for Vil9 and Vil27, Vil14 growth significantly slowed down after ~ 42 ka and finally stopped ~ 29 ka ago where the δ 13C increase suggests a strong climate deterioration that coincides with both North Atlantic sea level and sea surface temperature drop.

Simulation of heat and mass transfer in spray chambers

A physicochemical model has been constructed for heat and mass transfer between the gas and the liquid drops in a spray chamber. The model takes into account the effect of the Stefan flow on mass transfer at high vapor contents of the gas and on the variability of the drop mass due to phase transitions. An approximate formula is presented for deriving the drop surface temperature from the mass-average drop temperature and the thermophysical parameters of the liquid and the gas-vapor flow. The calculated data are compared with available experimental data.

Paleoceanography of the mid-Pleistocene South China Sea

High-frequency fluctuations in paleoenvironmental proxies from the South China Sea, including stable isotopes and abundance of planktonic foraminifers, nannofossils, radiolarians, and palynomorphs, reveal a dynamic local response to the stepwise development of the mid-Pleistocene climate transition (MPT). These proxies indicate a dramatic drop in sea surface temperature (SST) at about 900 ka, the first largest SST decrease in the region during the Quaternary. Estimated winter SST declined from 24–25 °C to 17–18 °C in the northern and from 26–27 °C to 23–24 °C in the southern South China Sea. Subsequent changes in the thermocline depth and faunal–floral turnovers imply a period of about 300 ka in the final stage of the MPT. Winter monsoons increased at ∼900 ka and reached a maximum strength toward the end of the MPT when summer monsoons also strengthened in interglacials. As a result, thermal gradient between the northern and southern South China Sea increased substantially, with stronger winter monsoon influence in the north and warm and saline conditions in the south especially during glacial periods. These N–S paleoceanographic contrasts indicate an initial establishment of the modern-styled semi-enclosed South China Sea about 900 ka ago when passages in the south started to become completely exposed during glacial lowstands. Coupled with deep water cooling and ventilation, uplift of the sill depth in the Bashi Strait to near the present-2400 m during this period caused sudden decline and extinction of Pacific Deep Water benthic foraminifers in the isolated deep sea basin. Together with data from the oceanic western Pacific, these results further imply a considerable weakening of the western Pacific warm pool during MIS 23-22 and in subsequent glacial periods. While the MPT may have invoked high latitude processes especially an increased ice volume, tropical processes more likely have facilitated the restoration of heat and energy to the western Pacific in each interglacial rebound. Planktonic δ 13C maxima on eccentricity periocities leading major cooling events during the Quaternary indicate the important role of global carbon reservoir changes due to low as well as high latitude processes in past climate change.

Jet impingement quenching phenomena for hot surfaces well above the limiting temperature for solid–liquid contact

Experiments were conducted to understand the phenomena that happen just after a subcooled free-surface circular water jet impinges on a high temperature surface. A 2 mm-water-jet of 5–80 K subcooling and 3–15 m/s velocity was impinged on the flat surface of a cylindrical steel/brass block that was preheated to 500–600 °C. The transient temperature data were recorded and used to predict the surface temperature by an inverse heat conduction technique. A high-speed video camera was also employed to capture the flow condition. It is found that for a certain period of time the surface temperature remains well above the thermodynamic limiting temperature that allows stable solid–liquid contact. What happens during this period and what makes the surface temperature drop to the limiting temperature are important questions whose possible answers are given in this article. The cooling curves at the center of the impinging surface for different experimental conditions are also explained in relation with the limiting temperature and three characteristic regions having different types of flow patterns are identified.

ORIGINAL ARTICLE: Mass extinctions in the Azores during the last glaciation: fact or myth?

AbstractAim The influence of the last glaciation on the shallow‐water marine malacofauna of the Azores Islands is reviewed. We test, for this fauna, the ‘Pleistocene temperature theory’ of J.C. Briggs, which hypothesizes that a (supposed) lack of endemics in the older (Azorean endemic) fauna resulted from extinctions caused by a severe drop in sea surface temperatures during the Pleistocene.Location Santa Maria Island, Azores, Portugal.Methods We compare the fossil mollusc fauna of Prainha, Praia do Calhau and Lagoinhas Pleistocene outcrops with the recent mollusc fauna of the Azores Islands. We dated the fossil fauna, using shells of Patella aspera Röding, 1798, by standard U/Th methodology at the GEOTOP laboratory (Université du Québec à Montreal, Canada).Results Dating of the shells of P. aspera indicates that the deposition of the lower unit of the Prainha outcrop corresponded to Marine Oxygen Isotope Substage 5e (MISS 5e). Not a single endemic Azorean species of mollusc that is present in the Pleistocene fossil record has since become extinct, and we found no signs of ‘mass extinctions’ in the littoral marine molluscs of the Azores. The only species that were extirpated from these islands were thermophilic molluscs and littoral bivalves living in fine sand.Main conclusions Our results do not support Briggs’‘Pleistocene temperature theory’. Nor did we find evidence supporting the hypothesis that most of the marine organisms now present in the Azores recolonized the islands after the last glacial maximum.

Modelling the mean temperatures used for calculating heat and mass transfer in sprays

This paper deals with a variation on the approach to the modelling of sprays developed by Beck, J.C., Watkins, A.P., 2003a. On the development of a spray model based on drop-size moments. Proc. R. Soc. Lond. A 459 1365. In that model the size information concerning the spray is obtained by solving transport equations for two moments of the drop number size distribution, and their respective mean velocities, and obtaining two other moments from an assumed size distribution. The sub-models required for hydrodynamic phenomena, such as drop drag, break-up and collisions, have been presented in Beck, J.C., Watkins, A.P., 2002. On the development of spray sub-models based on droplet size moments. J. Comp. Phys. 182 586–621. The heat and mass transfer sub-models are described in Beck, J.C., Watkins, A.P., 2003b. The droplet number moments approach to spray modelling: the development of heat and mass transfer sub-models. Int. J. Heat and Fluid Flow 24 242–259. A single transport equation for the energy of the liquid phase is solved from which the local value of the volume-average liquid temperature is obtained. Consequently all the heat and mass transfer phenomena are related to this temperature. In practice it is the drop surface temperature that determines the heat and mass transfer rates. This paper explores the development and application of a simple model that assumes a parabolic temperature profile within individual drops to calculate a surface-area-average temperature for the spray locally. The models are applied to the simulation of sprays having assumed drop size distributions with Sauter mean radii at inlet in the 7–70 μm range. The use of surface-area-averaged temperatures, in place of volume-averaged ones, results in substantially higher levels of mass being evaporated from the drops. This is predominantly because of the increased film mean temperature and resulting increases in the vapour pressure in the film. The effects of the fuel used are also explored. The role of the vapour pressure in the film is again found to be the important parameter determining the different mass transfer rates for the different fuels. Comparisons made with spray penetration data of diesel fuel for a wide range of injector and ambient gas conditions indicate that the model reacts correctly to changes in these parameters. Comparisons are also made with measured liquid velocities and mean drop sizes. The importance of break-up and collision models on both the hydrodynamics and the heat and mass transfer in simulations made with the larger drops at inlet is demonstrated.