On this page we list research areas covered by members of the RMI “meteorological and climatological research” scientific service in the frame of hydrometeorology and land surface processes. Moreover, historical steps on past research done at RMI are given as background.

General information on RMI research and history can be found on the main RMI web site.

Various observation techniques have been developed to quantify the land surface processes at all spatio-temporal scales. Those measurements are combined with baseline physics to elaborate numerical models able to describe the interactions between the Earth surface and the atmosphere. Land surface modelling is for instance embedded in climate models at the global scale, in regional weather prediction models and in hydrometeorological models operated at the water catchment scale. They are used as lower boundary condition in atmospheric models and upper boundary in hydrological modelling.
The hydrometeorological modelling unit of RMI is especially involved in surface processes modelling and monitoring. It is in particular active in

• Research and operation of numerical weather prediction in Belgium and Europe through leading and participation to the Aladin consortium; the SURFEX modelling is used in that framework;
• Research and operations for actual evapotranspiration and land surface fluxes monitoring at continental scale (Europe, Africa, Eastern part of South America) through developments made in the frame of EUMETSAT LSA SAF (See RMI contribution to LSA SAF for more details);
• Research and developments based on exploitation of past observations and new opportunities offered by satellite remote sensing for evapotranspiration, land surface fluxes and soil moisture quantification at different spatial scales (see on-going ‘Projects’);
• Research and collaboration in micrometeorology for observation of land surface fluxes and related variables at local scale. Such observations are used for the validation of the developed land surface algorithms.

RMI has started its activity in hydrometeorology in developing in 1966 a specific network of analogic meteorological observations dedicated to measure simultaneously the full set of variables needed to quantify potential evapotranspiration and to feed its hydrological model. The water evaporation was first studied (Bultot and Dupriez, 1968, 1973) and followed by the assessment of the potential evapotranspiration of grass (Bleiman, 1976). The method was then generalized to main classes of vegetation (Bultot et al., 1983) and applied to the observations of the hydrometeorological network (Gellens-Meulenberghs and Gellens, 1992).

The development of the automatic weather stations network in the 1990s has progressively replaced the old synoptic and hydrometeorological networks. It has allowed to evaluate actual evapotranspiration, latent and sensible heat fluxes in a selection of stations through a combination of the profile and energy balance approach (Gellens-Meulenberghs, 2005, 2006).

The ‘SCHEME’ hydrological model has been developed at RMI and is applied for different purposes. In particular, it is used as a tool involved in the validation of products developed in the frame of EUMETSAT H SAF. See RMI contribution to H SAF for more details.

History:
Since many years, RMI has developed its own bucket hydrological model (Bultot and Dupriez, 1976a, 1985) suited for application at daily time step to medium size catchments (e.g. Bultot and Dupriez, 1976b; Bultot et al., 1981). That model has been further developed to cover two major water basins in Belgium (the Meuse and the Scheldt rivers). That model version is named the ‘SCHEME’ model, referring to those two water catchments.

Meteorological observations form with modelling the material used to study the evolution of climate. Statistics made on long time series of standardized observations are applied to define the characteristics of the past and current climate, as well as its evolution. A special attention is paid to the quantification of the extreme events occurrence which impacts directly the society in Belgium.

History:
Different RMI services contribute to the analysis of meteorological observations. In the early nineties, the publication of Sneyers (1990) is become a reference to characterize the main meteorological variables and the occurrence of extreme events. In parallel and afterwards, the study of the extreme precipitation has been conducted in different ways, i.e. using monthly resampling (Demarée, 1990; Buishand and Demarée, 1990) and regional approaches (Gellens, 2003; Van de Vyver, 2012). The establishment of Intensity-Duration-Frequency (IDF) curves based on statistical fitting of the extremes distribution is amongst the most popular user oriented product derived from these approaches, involving theoretical developments and applications (Demarée et al., 1998; Mohymont and Demarée, 2006; Van de Vyver and Demarée, 2010; Demarée and Van de Vyver, 2013; Van de Vyver, 2015).

RMI Meteorological and Climatological Research scientific service is especially involved in the climate study. Look e.g. to RMI leading activity in Cordex.be.

History:
Climate characterization and evolution are studied since many years at RMI which has also done pioneer work through early climate and land use change impact studies in Belgium and abroad, like in Switzerland and Kenya (e.g. Bultot et al., 1988 a, b, 1992, 1994, Gellens et al., 2000). Recently, those activities have been widely developed through various research activities, mainly supported by Belgian Science Policy funds.

Bleiman, N., 1976 : Estimation des valeurs journalières de l’évapotranspiration d’une nappe d’eau libre et de l’évapotranspiration potentielle du gazon à Uccle (50°48’N, 4°21’E, 100 m) pour la période 1901-1975). Inst. Roy. Mét. Pub., Miscellanea, Série A, N°5, Uccle-Bruxelles.

Buishand, T.A. and Demarée, G.R., 1990: Estimation of the annual maximum distribution from samples of maxima in separate seasons.

Bultot, F. and Dupriez, G. L., 1968: Le bac évaporatoire en usage dans le réseau hydrométéorologique belge. Bull. Assoc. Inst. Sci. Hydrol., 13(2), 163-168.

Bultot, F. and Dupriez, G. L., 1973: L’évaporation d’un bac d’eau libre - Sa signification restreinte. J. Hydrol., 20, 83-95.

Bultot, F. and Dupriez, G. L., 1976a: Conceptual hydrological model for an average-sized catchment area. J. Hydrol., 29, 251-292.

Bultot, F. and Dupriez, G. L., 1976b: Bilans hydriques et données hydrologiques pour la conception de projets de mise en valeur des ressources en eau dans les bassins hydrographiques belges, I. Bassin de la Semois. Publ. IRM (Bruxelles), série A, n° 96, 147 p.

Bultot, F. and Dupriez, G. L., 1985: Daily effective evapotranspiration from a river basin. In: Casebook on Operational Assessment of Areal Evaporation. Oper. Hydrol. Rep., 22 (WMO-N° 635), 80-105.

Bultot, F., Coppens, A. and Dupriez, G. L., 1983: Estimation de l’évapotranspiration potentielle en Belgique (procédure révisée). Pub. IRM, Série A, N°85, Uccle-Bruxelles, 28 pp.

Bultot, F., Dupriez, G. L. and Gellens, D., 1988a: Estimated annual regime of energy-balance components, evapotranspiration and soil moisture for a drainage basin in the case of a CO2 doubling. Climatic Change, 12 (1), 39-56.

Bultot, F., Coppens, A., Dupriez, G. L., Gellens, D. and Meulenberghs, F.,1988b: Repercussions of a CO2 doubling on the water cycle and on the water balance - A case study for Belgium. J. Hydrol., 99, 319-347.

Bultot, F., Dupriez, G. L. and Basiaux, A., 1981: Bilans hydriques et données hydrologiques pour la conception de projets de mise en valeur des ressources en eau dans les bassins hydrographiques belges, II. Bassin de la Dyle. Publ. IRM (Bruxelles), série A, n° 107, 149 p.

Bultot, F., Gellens, D., Spreafico, M. and Schädler, B., 1992: Repercussions of a CO2 doubling on the water balance - A case study in Switzerland. J. Hydrol., 137, 199-208.

Bultot, F., Gellens, D., Schädler, B.and Spreafico, M , 1994: Effects of climate change on snow accumulation and melting in the Broye catchment (Switzerland). Climate Change, 28, 339-363.

Demarée, G.R., 1990: Klimatologische en hydrologische aspecten van de intensiteit van de neerslag te Ukkel en de theorie van de extreme waarden verdelingen. Doctoraatsproefschrift, Faculteit Wetenschappen, Vrije Universiteit Brussel, september 1990.

Demarée, G.R. and Van de Vyver, H., 2013: Construction of intensity-duration-frequency (IDF) curves for precipitation with annual maxima data in Rwanda, Central Africa. Advances in Geosciences, 11, 1-5.

Demarée, G., Derasse, S. and Assani, A., 1998: Extreme value distributions of the rainy season maximum precipitation depths at Lubumbashi (Shaba), Zaire. In: Proceedings International Conference ‘Tropical Climatology, Meteorology and Hydrology in memoriam Franz Bultot (1924-1995)’, Brussels, 22-24 May 1996, 507-515.

Gellens, D., 2003: Etude des précipitations extrêmes. Etablissement des fractiles et des périodes de retour d’événements pluviométriques. Thèse présentée en vue de l’obtention du grade de docteur en Sciences. ULB, 242 pp.

Gellens, D., Barbieux, K., Schädler, B., Roulin, E., Aschwanden, H. and Gellens-Meulenberghs, F., 2000: Snow cover modelling as a tool for climate change assessment in a Swiss Alpine catchement. Nordic Hydrology, 31 (2), 73-88.

Gellens-Meulenberghs, F., 2005: Sensitivity tests of an energy balance model to choice of stability functions and measurement accuracy. Boundary-Layer Meteorology, DOI: 10.1007/s10546-004-5640-9, 115(3), 453-471.

Gellens-Meulenberghs, F, 2006: Validation et modélisation de l’évapotranspiration sur la Belgique. Thèse présentée en vue de l’obtention du grade de docteur en Sciences. UCL, 331 pp.

Gellens-Meulenberghs, F., Gellens, D., 1992: L'évapotranspiration potentielle en Belgique: variabilité spatiale et temporelle. Publ. IRM, série A, N° 130, 38 pp.

Mohymont, B. and Demarée, G.R., 2006: Etablissement de courbes Intensité-Durée-Fréquence des précipitations pour la station de Yangambi au moyen de différents modèles du type Montana. Hydrological Sciences – Journal – des Sciences Hydrologiques, 51(2), p. 239-253.

Sneyers, R., 1990: On the statistical analysis of series of observations. WMO Technical Note N° 415.

Van de Vyver, H. 2012: Spatial regression models for extreme precipitation in Belgium. Water Resources Research 48 W09549.

Van de Vyver, H., 2015: Bayesian estimation of rainfall intensity–duration–frequency relationships. Journal of Hydrology 529 1451—1463.

Van de Vyver, H. and Demarée, G. R., 2010: Construction of Intensity–Duration–Frequency (IDF) curves for precipitation at Lubumbashi, Congo, under the hypothesis of inadequate data. Hydrol. Sci. J. 55(4), 555–564.