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Mermoz S.,National Institute of Scientific Research | Mermoz S.,CNRS Center for the Study of the Biosphere from Space | Allain-Bailhache S.,University of Rennes 1 | Bernier M.,National Institute of Scientific Research | And 3 more authors.
IEEE Transactions on Geoscience and Remote Sensing | Year: 2014

River ice has an important effect on natural processes and human activities in northern countries. Current models for estimating river ice thickness are mostly based on environmental data. They require several inputs and yield only a global estimate of ice thickness for a large heterogeneous area. Attempts have been made intending to retrieve river ice thickness from remote sensing using monopolarized C-band radar data. No reliable maps of ice thickness have been produced. In this paper, the potential of polarimetric synthetic aperture radar (PolSAR) data for estimating river ice thickness is demonstrated, and a river ice thickness retrieval model is proposed. The C-band SAR images used in this paper were acquired by Radarsat-2 in the winter of 2009 over the Saint-François River (Southern Quebec), the Koksoak River (Northern Quebec), and the Mackenzie River (Northwest Territories) in Canada. Field campaigns were carried out to obtain ice thickness validation data at 70 locations. Polarimetric entropy was used to obtain ice thickness estimates. This approach results in spatially distributed ice thickness maps for selected ice types. © 1980-2012 IEEE.

News Article | November 12, 2016
Site: www.prweb.com

Mediaclip is proud to announce that its CEO, Marion Duchesne, was awarded the “Internationally Active Entrepreneur” prize at the 16th Quebec Business Women Awards Gala. The event took place on November 9 and was sponsored by The Network of Quebec Business Women, in collaboration with the Government of Quebec, Nelly De Vuyst and Videotron Business Solutions. Ten winners were crowned in 10 categories in front of more than 900 spectators who gathered at the Palais des Congrès in Montreal. The competition recognizes exceptional businesswomen who are distinguished, influential and have compiled a career marked with eloquent achievements, creativity, leadership, determination and generous commitment. Each candidate’s portfolio underwent rigorous analysis by a selection committee that chose, based on specific criteria, a number of portfolios in each of the 10 categories. These records were then reviewed by an independent selection panel chaired by Ms. Mary-Ann Bell, Corporate Director – Cogeco, Cominar, Gaz Métro (Valener), National Institute of Scientific Research and NAV Canada. The jury selected 30 finalists; from these, a winner was named in each category. Marion Duchesne, winner of the “Internationally Active Entrepreneur” prize was awarded this honor for her passion, her drive and vision, and her leadership that propelled Mediaclip beyond the borders of Canada with a presence in over 30 countries on 5 continents. To find out more about this achievement or about Mediaclip’s award-winning software, contact us at info(at)mediaclip(dot)ca.

Esmaeilzadeh H.,University of Tehran | Arzi E.,University of Tehran | Mozafari M.,Niroo Research Institute | Hassani A.,National Institute of Scientific Research
Sensors and Actuators, A: Physical | Year: 2012

A broadband optical fiber based inline polarizer (OFIP) for telecom wavelength division multiplexing (WDM) systems is fabricated by coating of Al and Au layers on opposite sides of an etched multimode fiber. We demonstrated that the cladding residual thickness δ = 0 μm optimizes the OFIP design for the maximum extinction ratio (ER) of 17.1 dB/cm, at both telecom wavelengths of 1550 nm and 1310 nm. In addition to the broadband characteristics of this OFIP, the optimal ER value which is identical for both telecom regimes makes our OFIP even more desirable for WDM systems. Finally, our OFIP is very cheap and miniaturized which also makes it very attractive in commercialization point of view. © 2012 Elsevier B.V.

Ouarda T.B.M.J.,National Institute of Scientific Research | Ouarda T.B.M.J.,Masdar Institute of Science and Technology | Charron C.,Masdar Institute of Science and Technology | Chebana F.,National Institute of Scientific Research
Energy Conversion and Management | Year: 2016

This paper reviews the different criteria used in the field of wind energy to compare the goodness-of-fit of candidate probability density functions (pdfs) to wind speed records, and discusses their advantages and disadvantages. The moment ratio and L-moment ratio diagram methods are also proposed as alternative methods for the choice of the pdfs. These two methods have the advantage of allowing an easy comparison of the fit of several pdfs for several time series (stations) on a single diagram. Plotting the position of a given wind speed data set in these diagrams is instantaneous and provides more information than a goodness-of-fit criterion since it provides knowledge about such characteristics as the skewness and kurtosis of the station data set. In this paper, it is proposed to study the applicability of these two methods for the selection of pdfs for wind speed data. Both types of diagrams are used to assess the fit of the pdfs for wind speed series in the United Arab Emirates. The analysis of the moment ratio diagrams reveals that the Kappa, Log-Pearson type III and Generalized Gamma are the distributions that fit best all wind speed series. The Weibull represents the best distribution among those with only one shape parameter. Results obtained with the diagrams are compared with those obtained with goodness-of-fit statistics and a good agreement is observed especially in the case of the L-moment ratio diagram. It is concluded that these diagrams can represent a simple and efficient approach to be used as complementary method to goodness-of-fit criteria. © 2016 Elsevier Ltd

Chandran A.,Masdar Institute of Science and Technology | Basha G.,Masdar Institute of Science and Technology | Ouarda T.B.M.J.,Masdar Institute of Science and Technology | Ouarda T.B.M.J.,National Institute of Scientific Research
International Journal of Climatology | Year: 2016

In this study, we investigate the influence of global climate oscillations on the local temperature and precipitation over the United Arab Emirates (UAE), which is one of the driest regions in the world with very high temperatures and low precipitation. The identification and assessment of remote interactions (teleconnections) are carried out by using ground station and gridded data sets. Monthly rainfall data from six ground stations over the UAE for the period of 1982-2010 is used in this study along with the long-term gridded precipitation and temperature data from the Global Precipitation Climatology Center and Global Historic Climatic Network. Linear correlations, wavelet analysis, and cross-wavelet analysis have been applied to identify the relation between climate indices and precipitation (temperature). The analysis reveals that the strong variability in precipitation is closely associated with the Southern Oscillation Index (SOI) and the Indian Ocean Dipole Index (IOD) during the months of August-March, September-January, respectively. In case of temperature, the strong variability is associated with the North Atlantic Oscillation Index (NAO) and the East Atlantic Oscillation Index (EAO) during the months of April-October, July-December. Spatial analysis of cross-wavelet reveals that the winter precipitation is significantly influenced by SOI and temperature during summer by the NAO. This research concludes that the negative phases of SOI (NAO) play a significant role in the increase of precipitation (decrease in summer temperatures) over the UAE region. © 2016 Royal Meteorological Society.

Niranjan Kumar K.,Masdar Institute of Science and Technology | Ouarda T.B.M.J.,Masdar Institute of Science and Technology | Ouarda T.B.M.J.,National Institute of Scientific Research | Sandeep S.,Abu Dhabi University | Ajayamohan R.S.,Abu Dhabi University
Climate Dynamics | Year: 2016

The climate variability on Earth is strongly influenced by the changes in the Sea Surface Temperature (SST) anomalies in the tropical oceans. More specifically, the inter-annual climate variability in the tropics as well as extra-tropical areas has large impact due to the anomalous SSTs in the tropical Pacific coupled with the El Niño Southern Oscillation (ENSO) through atmospheric teleconnections. However, the effect of ENSO on Middle Eastern region, specifically the Arabian Peninsula (AP) is marginally explored in previous studies. Hence, this study explicitly focuses on the assessment of ENSO variability and its winter climate teleconnections to the AP using the Community Atmospheric Model Version 4.0 (CAM4) simulations and Reanalysis datasets. ENSO teleconnections are also evaluated based on two sensitivity experiments (ENSO-related and ENSO-unrelated) using the CAM4 model. It is observed that during El Niño years the peninsular region receives more rainfall through enhanced moisture transport associated with anomalous westerly winds from adjoining Seas. The Rossby wave energy propagation in the atmosphere underlies important teleconnections involving ENSO. It is also noticed that there exist a distinct change in the phase of the Rossby wave pattern during El Niño and La Niña years which further causes the shift in the position of the jet stream over the Middle East. © 2016 Springer-Verlag Berlin Heidelberg

Charron C.,Masdar Institute of Science and Technology | Ouarda T.B.M.J.,Masdar Institute of Science and Technology | Ouarda T.B.M.J.,National Institute of Scientific Research
Journal of Hydrology | Year: 2015

Several studies have shown that improvements in the regional prediction of low-flow characteristics can be obtained through the inclusion of a parameter characterising catchment baseflow recession. Usually, a linear reservoir model is assumed to define recession characteristics used as predictors in regional models. We propose in this study to adopt instead a non-linear model. Predictors derived from the linear model and the non-linear model are used separately in low-flow regional models along with other predictors representing physiographical and meteorological characteristics. These models are applied to selected gaged catchments. Results show that better performances are obtained with the parameter from the non-linear model. One drawback of using recession parameters for regional estimation is that a streamflow record is required at the site of interest. However, recession parameters can be estimated with short streamflow records. In this study, to simulate the performances obtained at partially gaged catchments, the recession parameters are estimated with very short streamflow records at target sites. Results indicate that, with a streamflow record as short as one year, a model with a recession parameter from the non-linear model leads to better performances than a model with only physiographical and meteorological characteristics. © 2015 Elsevier B.V.

Hoang H.K.,McMaster University | Bernier M.,National Institute of Scientific Research | Duchesne S.,National Institute of Scientific Research | Tran Y.M.,Vietnam Academy of Science and Technology
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2016

The strong temporal backscatter signature of rice growing above the water's surface allows for the use of synthetic aperture radar (SAR) for paddy rice crop mapping in Southern Vietnam (Mekong Delta). In Northern Vietnam (Red River Delta), rice mapping using SAR is a challenge and is rarely performed because of the complex land-use/land-cover. Nevertheless, information about rice fields is needed for hydrological simulations in river basins such as the Cau River basin. The objective of this research is to investigate the potential of RADARSAT-2 band- C in identifying rice fields over a large and fragmented land-use area. Two methods are proposed, one for each data type, adapted to the land-use/land-cover of the study area. The thresholding technique, with a statistical analysis of the temporal variation of rice backscattering, was applied to the HH like-polarized ratio of dual-pol data. The support vector machine (SVM) algorithm was applied to the full quad-pol and a single HH-polarization calculated from polarimetric data. This study demonstrates that RADARSAT-2 dual- and quad-pol data can be successfully used to identify cultivated rice fields. However, the dual-pol data seems less efficient than the quad-pol data and the SVM classification is more flexible than the thresholding technique. Between the full quad-pol and a single polarization, the overall classification accuracy shows that the results derived from the single HH polarization are 3 to 10% less accurate than those derived from the classification of full quad-pol data. The results show the usefulness of polarimetric C-band data for the identification of rice fields in Northern Vietnam. © 2008-2012 IEEE.

Ouarda T.B.M.J.,Masdar Institute of Science and Technology | Ouarda T.B.M.J.,National Institute of Scientific Research | Charron C.,Masdar Institute of Science and Technology | Niranjan Kumar K.,Masdar Institute of Science and Technology | And 4 more authors.
Journal of Hydrology | Year: 2014

•Rainfall series in the UAE are analyzed for detection of trends and change points.•The modified M-K test is applied for the assessment of the significance of trends.•The original results lead towards a general decreasing trend in precipitations.•Bayesian analysis reveals an increasing trend with a downward shift in 1999.•Results indicate a seasonality change with rain occurring earlier in the winter. Arid and semiarid climates occupy more than 1/4 of the land surface of our planet, and are characterized by a strongly intermittent hydrologic regime, posing a major threat to the development of these regions. Despite this fact, a limited number of studies have focused on the climatic dynamics of precipitation in desert environments, assuming the rainfall input - and their temporal trends - as marginal compared with the evaporative component. Rainfall series at four meteorological stations in the United Arab Emirates (UAE) were analyzed for assessment of trends and detection of change points. The considered variables were total annual, seasonal and monthly rainfall; annual, seasonal and monthly maximum rainfall; and the number of rainy days per year, season and month. For the assessment of the significance of trends, the modified Mann-Kendall test and Theil-Sen's test were applied. Results show that most annual series present decreasing trends, although not statistically significant at the 5% level. The analysis of monthly time series reveals strong decreasing trends mainly occurring in February and March. Many trends for these months are statistically significant at the 10% level and some trends are significant at the 5% level. These two months account for most of the total annual rainfall in the UAE. To investigate the presence of sudden changes in rainfall time-series, the cumulative sum method and a Bayesian multiple change point detection procedure were applied to annual rainfall series. Results indicate that a change point happened around 1999 at all stations. Analyses were performed to evaluate the evolution of characteristics before and after 1999. Student's t-test and Levene's test were applied to determine if a change in the mean and/or in the variance occurred at the change point. Results show that a decreasing shift in the mean has occurred in the total annual rainfall and the number of rainy days at all four stations, and that the variance has decreased for the total annual rainfall at two stations. Frequency analysis was also performed on data before and after the change point. Results show that rainfall quantile values are significantly lower after 1999. The change point around the year 1999 is linked to various global climate indices. It is observed that the change of phase of the Southern Oscillation Index (SOI) has strong impact over the UAE precipitation. A brief discussion is presented on dynamical basis, the teleconnections connecting the SOI and the change in precipitation regime in the UAE around the year 1999. © 2014.

Basha G.,Masdar Institute of Science and Technology | Ouarda T.B.M.J.,Masdar Institute of Science and Technology | Ouarda T.B.M.J.,National Institute of Scientific Research | Marpu P.R.,Masdar Institute of Science and Technology
International Journal of Climatology | Year: 2015

This study discusses the evolution of temperature, precipitation and soil moisture patterns over the United Arab Emirates (UAE) region, which is characterized by hot climate and scarce precipitation. A stochastic model that reproduces non-stationary oscillation (NSO) processes by utilizing ensemble empirical mode decomposition (EEMD) and non-parametric techniques is used to predict the evolution of temperature, precipitation and soil moisture. The long-term gridded temperature, precipitation and soil moisture data from the Global Historic Climatic Network, Global Precipitation Climatology Center and Climate Prediction Center are used in this study. The data consists of 65 years of average monthly temperature and soil moisture measurements and 110 years of average monthly precipitation over the UAE. The last 20 years of observations of temperature, precipitation and soil moisture are reserved for the validation of the methodology and the rest of the data is used for prediction. The results show that future long-term patterns are well captured by the model and hence confirm the potential of the EEMD technique and the NSO resampling (NSOR) modelling process. The model is also used for forecasting the evolution of temperature, precipitation and soil moisture patterns for the next 30 years. This procedure is finally used to produce the spatial patterns of temperature, precipitation and soil moisture. Significant increase in temperature and decrease in precipitation and soil moisture are observed particularly over Abu Dhabi. The spatial map shows strong increase (decrease) in temperature (precipitation and soil moisture) over most of the UAE. The results are quite different for the south eastern part of the UAE. Western parts of the UAE are projected to see larger temperature increases than other parts. The results are coherent with the previous findings over this region. © 2015 Royal Meteorological Society.

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