Jean-Emmanuel Sicart's research while affiliated with Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement and other places

Publications (76)

Article
The recent field measurements of katabatic winds on steep alpine slopes provide a unique database for theoretical analysis of the mean flow development and the determination of mixing properties. The theory is based on the depth-integrated momentum and heat equations, and demonstrates an increase in mean velocity $U$ with downstream distance $x$ ac...
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A multi-experiment ensemble is performed using the WRF (Weather Research and Forecasting) model at high spatial resolution (1 km) over the Antisana glacier region (Ecuador), during the year 2005. Our goal is to identify the best model configurations to simulate atmospheric processes at diurnal and seasonal scales. The model is able to reproduce the...
Article
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The application of a distributed energy balance model over nine years at an hourly time step to a 20 × 20 m grid cell over Glacier Zongo (Bolivia, 16°S) enabled assessment of the climate factors that control the interseasonal and interannual variability of its surface mass balance. The model was validated by comparing the measured and simulated dis...
Preprint
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Clouds are an important component of the climate system, yet our understanding of how they directly and indirectly affect glacier melt in different climates is incomplete. Here we analyse high-quality datasets from 16 mountain glaciers in diverse climates around the globe to better understand how relationships between clouds and near-surface meteor...
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We describe a new field campaign over a steep, snowy \(30^{\circ }\) alpine slope, designed to investigate three recurrent issues in experimental studies of steep-slope katabatic winds. (1) Entrainment is known to be present in katabatic jets and has been estimated at the interface between the jet and the boundary layer above it. However, to our kn...
Article
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Study region The upper part of the Guayllabamba and Napo basins (78.2 ° W, 0.3 °S; 18,500 km²) in the equatorial Andes, which are vulnerable to stress on the ecosystem services. Study focus This paper analyses the diurnal cycle of precipitation over a transect from the Andes to the Amazon. The diurnal cycle is estimated as the diurnal distribution...
Preprint
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Amazonian deforestation has accelerated during the last decade, threatening an ecosystem where almost one third of the regional rainfall is transpired by the local rainforest. Due to the precipitation recycling, the southwestern Amazon, including the Amazon-Andes transition region, is particularly sensitive to forest loss. This study evaluates the...
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Atmospheric boundary layer (ABL) dynamics over glaciers mediate the response of glacier mass balance to large‐scale climate forcing. Despite this, very few ABL observations are available over mountain glaciers in complex terrain. An intensive field campaign was conducted in June 2015 at the Athabasca Glacier outlet of Columbia Icefield in the Canad...
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Katabatic winds are very frequent but poorly understood or simulated over steep slopes. This study focuses on a katabatic jet above a steep alpine slope. We assess the buoyancy terms in both the turbulence kinetic energy (TKE) and the Reynolds shear-stress budget equations. We specifically focus on the contribution of the slope-normal and along-slo...
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Snow interception by the forest canopy controls the spatial heterogeneity of subcanopy snow accumulation leading to significant differences between forested and nonforested areas at a variety of scales. Snow intercepted by the forest canopy can also drastically change the surface albedo. As such, accurately modeling snow interception is of importan...
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Snow interception by forest canopy drives the spatial heterogeneity of subcanopy snow accumulation leading to significant differences between forested and non-forested areas at a variety of scales. Snow intercepted by forest canopy can also drastically change the surface albedo. As such, accuratelly modelling snow interception is of importance for...
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In the tropical Andes, the identification of the present synoptic mechanisms associated with the diurnal cycle of precipitation and its interaction with orography is a key step to understand how the atmospheric circulation influences the patterns of precipitation variability on longer time-scales. In particular we aim to better understand the combi...
Article
We present the glacier-wide summer surface mass balances determined by a detailed hydrological balance ( sSMBhydro ) and the quantification of the uncertainties of the calculations on the Argentière and Mer de Glace-Leschaux drainage basins, located in the upper Arve watershed (French Alps), over the period 1996–2004. The spatial distribution of pr...
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Glaciers in the tropical Andes have been retreating for the past several decades, leading to a temporary increase in dry season water supply downstream. Projected future glacier shrinkage, however, will lead to a long-term reduction in dry season river discharge from glacierized catchments. This glacier retreat is closely related to the observed in...
Article
Glaciers in the tropical Andes have been retreating for the past several decades, leading to a temporary increase in dry season water supply downstream. Projected future glacier shrinkage, however, will lead to a long-term reduction in dry season river discharge from glacierized catchments. This glacier retreat is closely related to the observed in...
Article
Full-text available
Over Saint-Sorlin Glacier in the French Alps (45° N, 6.1° E; ∼ 3 km²) in summer, we study the atmospheric surface-layer dynamics, turbulent fluxes, their uncertainties and their impact on surface energy balance (SEB) melt estimates. Results are classified with regard to large-scale forcing. We use high-frequency eddy-covariance data and mean air-te...
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Over mountain glaciers, large errors may affect turbulent surface heat fluxes estimated with the bulk-aerodynamic (BA) method. That might lead to uncertainties in estimating melt from surface energy balance (SEB). During the summers of 2006 and 2009, in the atmospheric surface layer of Saint-Sorlin Glacier (French Alps, 45° N, 6.1° E, ~3 km2), mean...
Article
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The estimation of precipitation over the broad range of scales of interest for climatologists, meteorologists and hydrologists is challenging at high altitudes of tropical regions, where the spatial variability of precipitation is important while in situ measurements remain scarce largely due to operational constraints. Three different types of rai...
Article
The estimation of precipitation over the broad range of scales of interest for climatologists, meteorologists and hydrologists is challenging in high altitudes of tropical regions, where the spatial variability of precipitation is important while in situ measurements remain scarce largely due to operational constraints. Three different types of rai...
Article
Full-text available
Over glaciers in the outer tropics, during the dry winter season, turbulent fluxes are an important sink of melt energy due to high sublimation rates, but measurements in stable surface layers, in remote and complex terrains remain challenging. Eddy-covariance (EC) and bulk-aerodynamic (BA) methods were used to estimate surface turbulent heat fluxe...
Conference Paper
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Under tropical conditions, water discharge from glaciers is crucial for water resources in the dry season, as it is the case for La Paz, Bolivia (16S). In the current study, the glacier water supply of La Paz city has been assessed at annual and seasonal time-scale for the first time thanks to the mass balance analysis of 70 glaciers located within...
Article
We investigate properties of the turbulent flow and sensible heat fluxes in the atmospheric surface layer of the high elevation tropical Zongo glacier ( \(5,080\) m a.s.l., \(16^\circ \) S, Bolivia) from data collected in the dry season from July to August 2007, with an eddy-covariance system and a 6-m mast for wind speed and temperature profiles....
Article
The turbulent fluxes remain poorly understood on tropical glaciers. Studies based on the bulk method have shown that sublimation can be high during the dry season, reducing the energy available for melting. However, uncertainties on the bulk method are large, especially when katabatic flows cause a wind speed maximum at low height. Wind and tempera...
Conference Paper
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This presentation provides a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the last three decades is unprece...
Article
The general context of the study is to describe the changes in the mass balance and in the hydrological regime of the Zongo glacier in relation with the rainfall variability. The hypothesis considered is that the characteristics of the rainy season strongly influence the mass balance and the hydrological regime with a control on the fusion. A new d...
Article
Energy balance studies on glaciers mostly use aerodynamic profile methods, assuming hypotheses of Monin-Obukhov similarity theory are valid, in order to compute sensible and latent turbulent heat fluxes. Nevertheless, various turbulence measurements have shown that the turbulent flow in the surface layer is not in equilibrium and stationnary within...
Article
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The aim of this paper is to provide the community with a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the l...
Article
Full-text available
The aim of this paper is to provide the community with a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the l...
Article
Full-text available
Hydrometeorological observations are the basic material for a number of scientific and operational issues. They are required for studies aiming at understanding and/or modeling climate-environment-society interactions along with their spatial and temporal variations. They constitute also the basic information for estimating hydrological resources a...
Article
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Pour de nombreux domaines scientifiques ou opérationnels, l_observation hydrométéorologique est d_une importance capitale. Elle constitue la base principale de toutes les études et analyses visant à comprendre et/ou modéliser les interactions climat-environnement-société ainsi que leurs évolutions spatiales et temporelles. Elle est aussi l_informat...
Article
We present an estimate of the mass balance of the tropical glaciar at Zongo-Bolivia (we un­derstand as "mass balance" the mass gained or lost by the glacier in a given time interval); this estimate was carried out by two independent methods. We also analysed the balance's annual and monthly variability. We considered 15 hydrological years (1993-200...
Conference Paper
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In-situ measurements of glacial mass balance are scarce at the global scale. The World Glacier Monitoring Service compiles data from 110 of the 100,000 existing glaciers contained in the World Glacier Inventory. To better understand the climate-glacier relationship at a regional scale, and to study the influences of both morphological (exposure, sl...
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The causes and timing of tropical glacier fluctuations during the Holocene epoch (10,000 years ago to present) are poorly understood. Yet constraining their sensitivity to changes in climate is important, as these glaciers are both sensitive indicators of climate change and serve as water reservoirs for highland regions. Studies have so far documen...
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This paper describes several simple positive degree-day models (hereafter referred as "PDD models") designed to provide past climatic reconstruction from tropical glacier paleo-equilibrium altitude lines (paleo-ELA). Several ablation laws were tested and calibrated using the monthly ablation and meteorological data recorded from 1997 to 2006 on the...
Article
Glaciers offer an attractive proxy to document palaeoclimatic conditions at high elevation by providing additional constraints on regional precipitation patterns, and atmospheric temperature. However little is known about Holocene glacier fluctuations in the Andes and inferred climatic changes. Most recent studies on Holocene glacier fluctuations i...
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The longest continuous glaciological mass-balance time-series in the intertropical zone of South America goes back to 1991 on Glaciar Zongo, Bolivia. Photogrammetric and hydrological data have been used to (1) check the specific net balance over long periods and (2) extend the mass-balance time series over the last 50 years. These data reveal a bia...
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The influence of meteorological variables on snow/ice melting has been analyzed for two very contrasting months, in summer 2006, on Glacier de Saint-Sorlin, French Alps. July 2006 was the warmest July since 1950, and August 2006 was the coldest August since 1979. The total energy available for melting was just over half as much in August as in July...
Article
In the Andes several regions profit significantly from glacial melt water for drink water supply and electricity production. During the dry season, glacier melt is significant source of water in the semi-arid region of La Paz, Bolivia. The Andean glaciers are retreating and water resources after reaching a culmination, will decrease. This implicate...
Conference Paper
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Thanks to the IRD (Institut de Recherche pour l’Environnement, France) and local Andean institutions, a permanent observation network including glaciological mass balance, hydrological balance and locally, energy balance, could be maintained from 1991-1995 to date on a dozen of glaciers from Bolivia, Peru and Ecuador. We present a very synthetic vi...
Article
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We use meteorological data from two automatic weather stations (AWS) on Juncal Norte Glacier, central Chile, to investigate the glacier–climate interaction and to test ablation models of different complexity. The semi-arid Central Andes are characterized by dry summers, with precipitation close to zero, low relative humidity and intense solar radia...
Chapter
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Reconstructing climate over the last millennium is one major target of climate research. The extent of climate variability over recent centuries sets the scale on which ongoing climate changes can be measured. The quality of reconstructions of millennial temperatures in the northern hemisphere has greatly improved over the last decade (IPCC, 2007)....
Article
The turbulent fluxes remain poorly known on tropical glaciers characterized by very dry air at high altitude and low thermal seasonality. Different studies based on the bulk method have shown that sublimation can be important during the dry season, reducing the energy available for melting. However, uncertainties on the bulk method are large, espec...
Article
Full-text available
To determine the physical processes involved in the melting and disappearance of transient snow cover in nonglacierized tropical areas, the CROCUS snow model, interactions between Soil-Biosphere-Atmosphere (ISBA) land surface model, and coupled ISBA/CROCUS model have been applied to a full set of meteorological data recorded at 4795 m MSL on a mora...
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Esta sección 21 describe el tipo de información climática que se puede obtener del estudio del balance de masa. Los datos anuales se encuentran directamente relacionados con (i), la acumulación de nieve, la cual depende tanto de precipitaciones como de avalanchas de nieve o hielo y vientos; y (ii), la ablación, la cual representa directamente el Ba...
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A previous study of Fox [Fox, A.N. 1993. Snowline altitude and climate at present and during the Last Pleistocene Glacial Maximum in the Central Andes (5 degrees-28 degrees S). Ph.D. Thesis. Cornell University.] showed that for a fixed 0 degrees C isotherm altitude, the equilibrium-line altitude (ELA) of the Peruvian and Bolivian glaciers from 5 to...
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Esta sección 8 se inicia con una revisión de los principales resultados de las mediciones sobre la evolución de los glaciares tropicales. Luego, se analizan los datos de balance de masa en Bolivia y Ecuador desde principios de los noventa, para lo cual se ha utilizado información medida en toda la superficie del glaciar para resaltar el hecho de qu...
Article
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At high latitudes, longwave radiation can provide similar, or higher, amounts of energy to snow than shortwave radiation due to the low solar elevation (cosine effect and increased scattering due to long atmospheric path lengths). This effect is magnified in mountains due to shading and longwave emissions from the complex topography. This study exa...
Article
In mountainous, forested environments, snowcover dynamics exert a strong control on hydrologic and atmospheric processes. Snowcover ablation patterns in forests are controlled by a complex combination of depositional patterns coupled with radiative and turbulent heat flux patterns related to topographic and canopy cover variations. Quantification o...
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Observations of land surface and snowpack energetics and mass fluxes were made over arctic shrub tundra of varying canopy height and density using radiometers, eddy covariance flux measurements, and snow mass changes from snow surveys of depth and density. Over several years, snow accumulation in the shrubs was found to be consistently higher than...
Article
[1] Tropical glaciology includes investigation of climate variability in poorly documented regions of large surface-atmosphere energy exchanges. This study examines the surface energy fluxes of the Bolivian Zongo Glacier (16 degrees S, 68 degrees W, 6000 - 4900 m asl) in order to identify the atmospheric variables that control melting. Measurements...