Publications
188 results found
Sparks NJ, Hardwick SR, Schmid M, et al., 2017, IMAGE: a multivariate multi-site stochastic weather generator for European weather and climate, Stochastic Environmental Research and Risk Assessment, Vol: 32, Pages: 771-784, ISSN: 1436-3240
Capturing the spatial and temporal correlation of multiple variables in a weather generator is challenging. A new massively multi-site, multivariate daily stochastic weather generator called IMAGE is presented here. It models temperature and precipitation variables as latent Gaussian variables with temporal behaviour governed by an auto-regressive model whose residuals and parameters are correlated through resampling of principle component time series of empirical orthogonal function modes. A case study using European climate data demonstrates the model’s ability to reproduce extreme events of temperature and precipitation. The ability to capture the spatial and temporal extent of extremes using a modified Climate Extremes Index is demonstrated. Importantly, the model generates events covering not observed temporal and spatial scales giving new insights for risk management purposes.
Corsaro CM, Toumi R, 2017, A self-weakening mechanism for tropical cyclones, Quaterly Journal of the Royal Meteological Society, Vol: 143, Pages: 2585-2599, ISSN: 1477-870X
A mechanism leading to the self-weakening of tropical cyclones is proposed using the Weather and Research and Forecasting model. A comparison between an experiment with variable Coriolis parameter f and one on an f-plane shows that after the initial intensification the former is characterized by a smaller intensity. As opposed to the tropical cyclone on the f-plane, the one with variable f weakens significantly after reaching maturity. Analyses of the 3-D circulation show that the main reason for the weakening is dry intrusion in the mid-upper troposphere from the west. Once the dry intrusion reaches the inner vortex, strong downdrafts reduce the high equivalent potential temperature in the boundary layer inflow. The subsequent updrafts in the eyewall, characterized by lower equivalent potential temperature, are considerably reduced and, consequently, the secondary circulation weakens.Back-trajectories are used to determine the origin of the dry intrusion. It is found that the air parcels expelled from the storm deep convection into the outflow layer recirculate anticyclonically back into the vortex, causing a self-weakening of the tropical cyclone. A time span for the recirculation of at least 48 h allows the air parcels to sink substantially before reaching the vortex circulation. Some implications of the intrinsic nature of this process are briefly discussed.
Arcucci R, D'Amore L, Toumi R, 2017, Preconditioning of the background error covariance matrix in data assimilation for the Caspian Sea, 1st International Conference on Applied Mathematics and Computer Science (ICAMCS), Publisher: AIP Publishing, ISSN: 1551-7616
Data Assimilation (DA) is an uncertainty quantification technique used for improving numerical forecasted results by incorporating observed data into prediction models. As a crucial point into DA models is the ill conditioning of the covariance matrices involved, it is mandatory to introduce, in a DA software, preconditioning methods. Here we present first studies concerning the introduction of two different preconditioning methods in a DA software we are developing (we named S3DVAR) which implements a Scalable Three Dimensional Variational Data Assimilation model for assimilating sea surface temperature (SST) values collected into the Caspian Sea by using the Regional Ocean Modeling System (ROMS) with observations provided by the Group of High resolution sea surface temperature (GHRSST). We also present the algorithmic strategies we employ.
Phillipson L, Toumi R, 2017, Impact of data assimilation on ocean current forecasts in the Angola Basin, OCEAN MODELLING, Vol: 114, Pages: 45-58, ISSN: 1463-5003
The ocean current predictability in the data limited Angola Basin was investigated using the Regional Ocean Modelling System (ROMS) with four-dimensional variational data assimilation. Six experiments were undertaken comprising a baseline case of the assimilation of salinity/temperature profiles and satellite sea surface temperature, with the subsequent addition of altimetry, OSCAR (satellite-derived sea surface currents), drifters, altimetry and drifters combined, and OSCAR and drifters combined. The addition of drifters significantly improves Lagrangian predictability in comparison to the baseline case as well as the addition of either altimetry or OSCAR. OSCAR assimilation only improves Lagrangian predictability as much as altimetry assimilation. On average the assimilation of either altimetry or OSCAR with drifter velocities does not significantly improve Lagrangian predictability compared to the drifter assimilation alone, even degrading predictability in some cases. When the forecast current speed is large, it is more likely that the combination improves trajectory forecasts. Conversely, when the currents are weaker, it is more likely that the combination degrades the trajectory forecast.
Cahill B, Toumi R, Stenchikov G, et al., 2017, Evaluation of thermal and dynamic impacts of summer dust aerosols on the Red Sea, Journal of Geophysical Research: Oceans, Vol: 122, Pages: 1325-1346, ISSN: 2169-9275
The seasonal response of upper ocean processes in the Red Sea to summer-time dust aerosol perturbations is investigated using an uncoupled regional ocean model. We find that the upper limit response is highly sensitive to dust-induced reductions in radiative fluxes. Sea surface cooling of −1°C and −2°C is predicted in the northern and southern regions, respectively. This cooling is associated with a net radiation reduction of −40 W m−2 and −90 W m−2 over the northern and southern regions, respectively. Larger cooling occurs below the mixed layer at 75 m in autumn, −1.2°C (north) and −1.9°C (south). SSTs adjust more rapidly (ca. 30 days) than the subsurface temperatures (seasonal time scales), due to stronger stratification and increased mixed layer stability inhibiting the extent of vertical mixing. The basin average annual heat flux reverses sign and becomes positive, +4.2 W m−2 (as compared to observed estimates −17.3 W m−2) indicating a small gain of heat from the atmosphere. When we consider missing feedbacks from atmospheric processes in our uncoupled experiment, we postulate that the magnitude of cooling and the time scales for adjustment will be much less, and that the annual heat flux will not reverse sign but nevertheless be reduced as a result of dust perturbations. While our study highlights the importance of considering coupled ocean-atmosphere processes on the net surface energy flux in dust perturbation studies, the results of our uncoupled dust experiment still provide an upper limit estimate of the response of the upper ocean to dust-induced radiative forcing perturbations.
Arcucci R, D'Amore L, Pistoia J, et al., 2017, On the variational data assimilation problem solving and sensitivity analysis, JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 335, Pages: 311-326, ISSN: 0021-9991
We consider the Variational Data Assimilation (VarDA) problem in an operational framework, namely, as it results when it is employed for the analysis of temperature and salinity variations of data collected in closed and semi closed seas. We present a computing approach to solve the main computational kernel at the heart of the VarDA problem, which outperforms the technique nowadays employed by the oceanographic operative software. The new approach is obtained by means of Tikhonov regularization. We provide the sensitivity analysis of this approach and we also study its performance in terms of the accuracy gain on the computed solution. We provide validations on two realistic oceanographic data sets.
Nissan H, Toumi R, 2016, Regional modelling of rainfall erosivity: Sensitivity of soil erosion to aerosol emissions, Quarterly Journal of the Royal Meteorological Society, Vol: 143, Pages: 265-277, ISSN: 1477-870X
A rainfall erosivity scheme is implemented into the widely-used regional atmosphere-landmodel, WRF. Rainfall erosivity is parameterised from hourly precipitation and surface runoff in a high resolution (4 km) convection-permitting model. The scheme is used to examine thepotential effects of changes in atmospheric aerosol concentrations on soil erosion in a case study of northern India and the surrounding countries for the 2010 monsoon season, using a model which isolates the indirect effect on cloud microphysics only. This study offers a preliminary investigation into this emerging topic, but longer simulations would be needed to establish a robust signal.Summer precipitation is reduced in most areas and the monsoon circulation weakens for increases in cloud condensation nuclei concentrations. This can be attributed to localised cloud microphysical changes in the northeast of India, which induce a dynamic response opposing the monsoon circulation. The two regions of greatest decrease in erosion with increasing aerosolare in the Western Ghats and the Ganges Delta, both significant cropland areas. However, the effect is not uniform, with isolated local increases in soil erosion. These results suggest that, while efforts to reduce anthropogenic aerosol emissions may improve water availability for crops through enhanced rainfall, these benefits are likely to be tempered by an increase in soil erosion, though robust local changes were difficult to predict.
Trivedi A, Toumi R, 2016, Mechanisms of bottom boundary fluxes in a numerical model of the Shetland shelf, Ocean Dynamics, Vol: 67, Pages: 1-21, ISSN: 1616-7341
Across-slope bottom boundary layer (BBL) fluxes on the shelf-edge connectthis region to deeper waters. Two proposed ways in which across-slope BBLfluxes can occur, in regions that have a slope current aligned to the bathymetry, are:the frictional veering of bottom currents termed the ‘Ekman drain’; and through localwind-forced downwelling (wind-driven surface Ekman flow with an associated bottomflow). We investigate the variability, magnitude and spatial scale of BBL fluxeson the Shetland shelf, which has a prominent slope current, using a high-resolution(∼ 2 km) configuration of the MITgcm model. Fluxes are analysed in the BBL atthe shelf break near the 200 m isobath and are found to have a seasonal variabilitywith high/low volume transport in winter/summer respectively. By using a multivariateregression approach, we find that the locally wind-driven Ekman transport playsno explicit role in explaining daily bottom fluxes. We can better explain the variabilityof the across-slope BBL flux as a linear function of the speed and across-slopecomponent of the interior flow, corresponding to an Ekman plus mean-flow flux. Weestimate that the mean-flow is a greater contributor than the Ekman flux to the BBLflux. The spatial heterogeneity of the BBL fluxes can be attributed to the mean-flow,which has a much shorter decorrelation length compared to the Ekman flux. We concludethat both the speed and direction of the interior current determines the dailyBBL flux. The wind does not explicitly contribute through local downwelling, butmay influence the interior current and therefore implicitly the BBL fluxes on longertimescales.
Bruneau N, Toumi R, 2016, A fully-coupled atmosphere-ocean-wave model of the Caspian Sea, Ocean Modelling, Vol: 107, Pages: 97-111, ISSN: 1463-5011
Located in the mid-latitudes, the Caspian Sea is the largest enclosed basin in the world. A fully-coupled atmosphere-ocean-wave model of the Caspian Sea at high resolution (8 km) for a period of three years is presented. After validating each component of the modelling platform, the wave state of the Caspian Sea is studied. Results show very different wave regimes between the three different basins, a strong seasonality and an almost swell-free state. It is shown here that waves modify the horizontal eddy viscosity and vertical heat diffusion. However, due to a reasonably weak annual wave state, these effects are restricted to the upper-ocean layer (< 30 m) except during the most severe events (100 m).Three main experiments are conducted: 1) the ROMS ocean model forced by atmospheric reanalysis (CFSR), 2) ROMS coupled with the atmospheric model WRF and 3) the impact of wave-induced processes. The seasonality of the Caspian Sea is accurately captured in each experiment which highlights a rapid warming of the sea surface temperature (SST) in spring while the mixed layer depths (MLD) become very rapidly shallow (shifting from over 100 m to 15 m in two months). Contrarily, a gentle cooling of the SST accompanied with a deepening of the MLD is modelled during autumn and winter. The results also show a significant improvement of the model skill in the representation of the dynamics when ROMS is coupled to WRF.Finally, as ocean surface waves imply feedback at the interface atmosphere-ocean through the transfer of momentum, mass and heat, we investigate their potential effects on the Caspian Sea dynamics. Results are mixed and show a reasonably weak impact of wave-induced processes. While waves have a negligible effect during the winter as wave-induced mixing is confined to the MLD, the summer global SST are less accurately modelled due to the enhancement of mixing in shallow MLDs. However the SST bias, temperature at a subsurface location are improved.
Wang S, Toumi R, 2016, On the relationship between hurricane cost and the integrated wind profile, Environmental Research Letters, Vol: 11, ISSN: 1748-9326
It is challenging to identify metrics that best capture hurricane destructive potential and costs. Although it has been found that the sea surface temperature and vertical wind shear can both make considerable changes to the hurricane destructive potential metrics, it is still unknown which plays a more important role. Here we present a new method to reconstruct the historical wind structure of hurricanes that allows us, for the first time, to calculate the correlation of damage with integrated power dissipation and integrated kinetic energy of all hurricanes at landfall since 1988. We find that those metrics, which include the horizontal wind structure, rather than just maximum intensity, are much better correlated with the hurricane cost. The vertical wind shear over the main development region of hurricanes plays a more dominant role than the sea surface temperature in controlling these metrics and therefore also ultimately the cost of hurricanes.
Wang S, Toumi R, 2016, On the relationship between hurricane cost and the integrated wind profile, Environmental Research Letters, Vol: 11, ISSN: 1748-9326
It is challenging to identify metrics that best capture hurricane destructive potential and costs. Although it has been found that the sea surface temperature and vertical wind shear can both make considerable changes to the hurricane destructive potential metrics, it is still unknown which plays a more important role. Here we present a new method to reconstruct the historical wind structure of hurricanes that allows us, for the first time, to calculate the correlation of damage with integrated power dissipation and integrated kinetic energy of all hurricanes at landfall since 1988. We find that those metrics, which include the horizontal wind structure, rather than just maximum intensity, are much better correlated with the hurricane cost. The vertical wind shear over the main development region of hurricanes plays a more dominant role than the sea surface temperature in controlling these metrics and therefore also ultimately the cost of hurricanes.
Toumi R, wong B, 2016, Effect of extreme ocean precipitation on sea surface elevation and storm surges, Quarterly Journal of the Royal Meteorological Society, Vol: 142, Pages: 2541-2550, ISSN: 1477-870X
Ocean models that neglect mass and momentum contributions from precipitation can have asystematic bias in sea surface height (SSH). Here, a new rainfall scheme is introduced intothe Regional Ocean Modelling System (ROMS) to incorporate the effects of precipitationmass. When precipitation is added to the sea surface, it spreads out via surface gravity wavesthat increase in propagation speed with increasing water depth. Over several days, the SSHincrease due to the precipitation mass added created a geostrophic adjustment, generatinganti-cyclonic geostrophic currents around the SSH increase. The transfer of momentum fromprecipitation to the sea surface, or rain stress, can also be important. In the case study of areal tropical cyclone, Monica passing North Australia, the effect of incorporatingprecipitation mass is compared with other processes affecting the storm surge: surface wind,inverse barometer effect and rain stress. The maximum SSH response is 170.6 cm for thewind effect, 61.5 cm for the inverse barometer effect, 7.5 cm for the effect of rain stress and6.4 cm for the effect of rain mass. Each process has been shown to have different spatialinfluences. The effect of rain mass has a strong remote influence compared to the inversebarometer effect and the effect of rain stress. This is particularly seen in semi-enclosed bays.
Phibbs S, Toumi R, 2016, The dependence of precipitation and its footprint on atmospheric temperature in idealized extratropical cyclones, Journal of Geophysical Research: Atmospheres, Vol: 121, Pages: 8743-8754, ISSN: 2169-8996
Flood hazard is a function of the magnitude and spatial pattern of precipitation accumulation.The sensitivity of precipitation to atmospheric temperature is investigated for idealized extratropicalcyclones, enabling us to examine the footprint of extreme precipitation (surface area where accumulatedprecipitation exceeds high thresholds) and the accumulation in different-sized catchment areas. Themean precipitation increases with temperature, with the mean increase at 5.40%/∘C. The 99.9th percentileof accumulated precipitation increases at 12.7%/∘C for 1 h and 9.38%/∘C for 24 h, both greater thanClausius-Clapeyron scaling. The footprint of extreme precipitation grows considerably with temperature,with the relative increase generally greater for longer durations. The sensitivity of the footprint of extremeprecipitation is generally super Clausius-Clapeyron. The surface area of all precipitation shrinks withincreasing temperature. Greater relative changes in the number of catchment areas exceeding extremetotal precipitation are found when the domain is divided into larger rather than smaller catchment areas.This indicates that fluvial flooding may increase faster than pluvial flooding from extratropical cyclones in awarming world. When the catchment areas are ranked in order of total precipitation, the 99.9th percentile isfound to increase slightly above Clausius-Clapeyron expectations for all of the catchment sizes, from 9 km2to 22,500 km2. This is surprising for larger catchment areas given the change in mean precipitation. Wepropose that this is due to spatially concentrated changes in extreme precipitation in the occluded front
Toumi R, Wong B, 2016, Model study of the asymmetry in tropical cyclone-induced positive and negative surges, Atmospheric Science Letters, Vol: 17, Pages: 334-338, ISSN: 1530-261X
Storm surges pose significant threats to coastal communities, yet negative surges are not aswell understood as positive surges. In this study, idealized experiments of a tropical cycloneforcing a 3D ocean model are conducted to investigate the asymmetry of positive andnegative surges. Negative surges are larger in magnitude and extend further across thecoastline than positive surges. While positive surges are driven by wind blowing onshore,negative surges are largely dominated by alongshore winds, with horizontal divergence as themain mechanism. This asymmetry also increases with decreasing depth and increasinglatitude.
Poulain V, Bekki S, Marchand M, et al., 2016, Evaluation of the inter-annual variability of stratospheric chemical composition in chemistry-climate models using ground-based multi species time series, Journal of Atmospheric and Solar-Terrestrial Physics, Vol: 145, Pages: 61-84, ISSN: 1364-6826
The variability of stratospheric chemical composition occurs on a broad spectrum of timescales, ranging from day to decades. A large part of the variability appears to be driven by external forcings such as volcanic aerosols, solar activity, halogen loading, levels of greenhouse gases (GHG), and modes of climate variability (quasi-biennial oscillation (QBO), El Niño-Southern Oscillation (ENSO)). We estimate the contributions of different external forcings to the interannual variability of stratospheric chemical composition and evaluate how well 3-D chemistry-climate models (CCMs) can reproduce the observed response-forcing relationships. We carry out multivariate regression analyses on long time series of observed and simulated time series of several traces gases in order to estimate the contributions of individual forcings and unforced variability to their internannual variability. The observations are typically decadal time series of ground-based data from the international Network for the Detection of Atmospheric Composition Change (NDACC) and the CCM simulations are taken from the CCMVal-2 REF-B1 simulations database. The chemical species considered are column O3, HCl, NO2, and N2O. We check the consistency between observations and model simulations in terms of the forced and internal components of the total interannual variability (externally forced variability and internal variability) and identify the driving factors in the interannual variations of stratospheric chemical composition over NDACC measurement sites. Overall, there is a reasonably good agreement between regression results from models and observations regarding the externally forced interannual variability. A much larger fraction of the observed and modelled interannual variability is explained by external forcings in the tropics than in the extratropics, notably in polar regions. CCMs are able to reproduce the amplitudes of responses in chemical composition to specific external forcings. H
Broadbridge MB, Toumi R, 2015, The deep circulation of the Faroe-Shetland Channel:Opposing flows and topographic eddies, Journal of Geophysical Research: Oceans, Vol: 120, Pages: 5983-5996, ISSN: 2169-9291
New insights into the deep circulation of the Faroe-Shetland channel are gained from a highresolutionregional ocean model. The simulation shows a more complex structure of the deep flow fieldthan previously thought: a flow reversal of the deep and intermediate waters to the northeast on the Faroeseflank of the channel and persistent topographic eddies that force the deep currents into a gyre-likestructure. This flow reversal opposes the previously accepted understanding of a purely southwestwarddeep flow but is in agreement with velocity measurements. The southwestward transport of the overflowwaters is found to be facilitated almost exclusively by a strong and narrow current on the Shetland side ofthe channel. Float release experiments show that up to 38% of the overflow water takes longer than apurely southwestward flow regime suggests and up to 13% takes twice as long. From the release of tracers,a substantial amount of lateral mixing is evident within the channel, predominantly facilitated by the topographiceddies.
Tamura-Wicks H, Toumi R, Budgell WP, 2015, Sensitivity of Caspian sea-ice to air temperature, Quarterly Journal of the Royal Meteorological Society, Vol: 141, Pages: 3088-3096, ISSN: 1477-870X
Caspian sea ice concentration from satellite passive microwave data and surface daily air temperatures are analysed from 1978 to 2009. Relationships between mean winter air temperatures, cumulative freezing degree days (CFDD) and the sum of daily ice area (cumulative ice area) are found. These show that mean monthly air temperature of less than 5.5–9.5 °C, and a minimum CFDD of 3.6 ± 11.2 °C, are required for ice formation in the northern Caspian. Examination of climate projections from multi-model ensembles of monthly mean air temperatures suggest that the northern Caspian may be largely ice-free by 2100 for the highest emission scenario. An ocean–ice–atmosphere model of the Caspian shows weak sensitivities of the minimum CFDD to varied sea ice albedo and ice compressive strength. Sea level decline is found to reduce the minimum CFDD as well as promote the formation of higher concentration or ‘closed ice’.
Wang S, Toumi R, Czaja A, et al., 2015, An analytic model of tropical cyclone wind profiles, Quarterly Journal of the Royal Meteorological Society, Vol: 141, Pages: 3018-3029, ISSN: 1477-870X
A physically based analytic model (λ model) is presented to describe the wind profile of tropical cyclones in terms of the pressure deficit and a single shape parameter (λ). To test the λ model, an idealized full-physics numerical model is employed to provide wind-profile samples and also to show the influence of environmental temperature and the properties of initial vortices on tropical cyclone size. It is found that the λ model provides an accurate fit of the azimuthal wind profile at the top of the boundary layer. In the simulations, tropical cyclone size is sensitive to sea-surface temperature, upper tropospheric temperature and initial vortex structure. The numerical model confirms the assumed Gaussian distribution with width λ of the moist entropy in the boundary layer. A linear relationship between model cyclone size and inline image is found, in agreement with the λ model. The λ model predicts a weak relationship between tropical cyclone size and intensity, as is observed. In addition, the λ model suggests that change in tropical cyclone size should be closely related to angular momentum transport near the boundary layer, as has been found in observations. The good agreement of the λ model with the numerical model shows that the λ model could be a reasonable alternative for characterizing the wind structure of tropical cyclones with only one scaling parameter.
Bossay S, Bekki S, Marchand M, et al., 2015, Sensitivity of tropical stratospheric ozone to rotational UV variations estimated from UARS and Aura MLS observations during the declining phases of solar cycles 22 and 23, Journal of Atmospheric and Solar-Terrestrial Physics, Vol: 130-131, Pages: 96-111, ISSN: 1364-6826
The correlation between tropical stratospheric ozone and UV radiation on solar rotational time scales is investigated using daily satellite ozone observations and reconstructed solar spectra. We consider two 3-year periods falling within the descending phases of two 11-year solar cycles 22 (1991-1994) and 23 (2004-2007). The UV rotational cycle is highly irregular and even disappears for half a year during cycle 23. For the 1991-1994 period, ozone and 205 nm UV flux are found to be correlated between about 10 and 1 hPa with a maximum of 0.29 at ~5 hPa; ozone sensitivity (percentage change in ozone for 1 percent change in UV) peaks at ~0.4. Correlation during cycle 23 is weaker with a peak ozone sensitivity of 0.2. The correlation is found to vary widely, not only with altitude, but also from one year to the next with a rotational signal in ozone appearing almost intermittent. Unexpectedly, the correlation is not found to bear any relation with the solar rotational forcing. For instance, solar rotational fluctuations are by far the strongest during 1991-1992 whereas the correlation peaks at the end of 1993, a rotationally quiescent period. When calculated over sliding intervals of 1-year, the sensitivity is found to vary very strongly within both 3-year periods; it is almost negligible over the entire vertical profile during some 1-year intervals or reaches close to 1 around 2-5 mb for other intervals. Other sources of variability, presumably of dynamical origin, operate on the rotational spectral range and determine to a large extent the estimated solar rotational signal. Even considering 3 years of observations (corresponding to about 40 solar cycles), the extraction of the rotational solar signal does not appear to be robust during declining phases of 11-year solar cycles. As observational studies cover at best three 11-year solar cycles, it must be challenging to produce a reliable estimation of the 11-year solar cycle signal in stratospheric ozone, especially in
Newinger C, Toumi R, 2015, Potential impact of the colored Amazon and Orinoco plume on tropical cyclone intensity, Journal of Geophysical Research: Oceans, Vol: 120, Pages: 1296-1317, ISSN: 2169-9275
Hardwick SR, Toumi R, Pfeifer M, et al., 2015, The relationship between leaf area index and microclimate in tropical forest and oil palm plantation: Forest disturbance drives changes in microclimate, Agricultural and Forest Meteorology, Vol: 201, Pages: 187-195, ISSN: 0168-1923
Land use change is a major threat to biodiversity. One mechanism by which land use change influences biodiversity and ecological processes is through changes in the local climate. Here, the relationships between leaf area index and five climate variables – air temperature, relative humidity, vapour pressure deficit, specific humidity and soil temperature – are investigated across a range of land use types in Borneo, including primary tropical forest, logged forest and oil palm plantation. Strong correlations with the leaf area index are found for the mean daily maximum air and soil temperatures, the mean daily maximum vapour pressure deficit and the mean daily minimum relative humidity. Air beneath canopies with high leaf area index is cooler and has higher relative humidity during the day. Forest microclimate is also found to be less variable for sites with higher leaf area indices. Primary forest is found to be up to 2.5 °C cooler than logged forest and up to 6.5 °C cooler than oil palm plantations. Our results indicate that leaf area index is a useful parameter for predicting the effects of vegetation upon microclimate, which could be used to make small scale climate predictions based on remotely sensed data.
Sparks N, Toumi R, 2015, Numerical Simulations of Daytime Temperature and Humidity Crossover Effects in London, BOUNDARY-LAYER METEOROLOGY, Vol: 154, Pages: 101-117, ISSN: 0006-8314
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- Citations: 4
Nicholls JF, Toumi R, Stenchikov G, 2014, Effects of unsteady mountain-gap winds on eddies in the Red Sea, Atmospheric Science Letters, Vol: 16, Pages: 279-284, ISSN: 1530-261X
Phibbs S, Toumi R, 2014, Modeled dependence of wind and waves on ocean temperature in tropical cyclones, GEOPHYSICAL RESEARCH LETTERS, Vol: 41, Pages: 7383-7390, ISSN: 0094-8276
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- Citations: 7
Radu R, Toumi R, Phau J, 2014, Influence of atmospheric and sea surface temperature on the size of hurricane <i>Catarina</i>, QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Vol: 140, Pages: 1778-1784, ISSN: 0035-9009
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- Citations: 15
Nicholls JF, Toumi R, 2014, On the lake effects of the Caspian Sea, QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Vol: 140, Pages: 1399-1408, ISSN: 0035-9009
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- Citations: 37
White RH, Toumi R, 2014, River flow and ocean temperatures: The Congo River, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, Vol: 119, Pages: 2501-2517, ISSN: 2169-9275
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- Citations: 19
Nissan H, Toumi R, 2013, On the impact of aerosols on soil erosion, GEOPHYSICAL RESEARCH LETTERS, Vol: 40, Pages: 5994-5998, ISSN: 0094-8276
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- Citations: 3
White RH, Toumi R, 2013, The limitations of bias correcting regional climate model inputs, GEOPHYSICAL RESEARCH LETTERS, Vol: 40, Pages: 2907-2912, ISSN: 0094-8276
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- Citations: 66
Nissan H, Toumi R, 2013, Dynamic simulation of rainfall kinetic energy flux in a cloud resolving model, GEOPHYSICAL RESEARCH LETTERS, Vol: 40, Pages: 3331-3336, ISSN: 0094-8276
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- Citations: 7
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