Efthymios Nikolopoulos

Dr. Efthymios Nikolopoulos

Department of Civil and Environmental Engineering, University of Connecticut, Storrs, CT, USA
orcid

Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 January 2022 in Remote Sensing of Environment
Verified
Journal Article
Closed access
RPRajani Pradhan
Rajani Pradhan
YMYannis Markonis
Yannis Markonis
MGMijael Rodrigo Vargas Godoy
Mijael Rodrigo Vargas Godoy
Anahí Villalba-PradasAnahí Villalba-Pradas
Anahí Villalba-Pradas
KAKonstantinos Andreadis
Konstantinos Andreadis
MHMartin Hanel
Martin Hanel

1 September 2014 in Geomorphology
Verified
Journal Article
Closed access
ENEfthymios Nikolopoulos
Efthymios Nikolopoulos
SCStefano Crema
Stefano Crema
LMLorenzo Marchi
Lorenzo Marchi
FMFrancesco Marra
Francesco Marra
FGFausto Guzzetti
Fausto Guzzetti
MBMarco Borga
Marco Borga

1 October 2014 in Journal of Hydrometeorology
Verified
Journal Article
Closed access
Yiwen MeiYiwen Mei
Yiwen Mei
EAEmmanouil N. Anagnostou
Emmanouil N. Anagnostou
ENEfthymios Nikolopoulos
Efthymios Nikolopoulos
MBMarco Borga
Marco Borga
Accurate quantitative precipitation estimation over mountainous basins is of great importance because of their susceptibility to hazards such as flash floods, shallow landslides, and debris flows, triggered by heavy precipitation events (HPEs). In situ observations over mountainous areas are limited, but currently available satellite precipitation products can potentially provide the precipitation estimation needed for hydrological applications. In this study, four widely used satellite-based precipitation products [Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) 3B42, version 7 (3B42-V7), and in near–real time (3B42-RT); Climate Prediction Center (CPC) morphing technique (CMORPH); and Precipitation Estimation from Remotely Sensed Imagery Using Artificial Neural Networks (PERSIANN)] are evaluated with respect to their performance in capturing the properties of HPEs over different basin scales. Evaluation is carried out over the upper Adige River basin (eastern Italian Alps) for an 8-yr period (2003–10). Basin-averaged rainfall derived from a dense rain gauge network in the region is used as a reference. Satellite precipitation error analysis is performed for warm (May–August) and cold (September–December) season months as well as for different quantile ranges of basin-averaged precipitation accumulations. Three error metrics and a score system are introduced to quantify the performances of the various satellite products. Overall, no single precipitation product can be considered ideal for detecting and quantifying HPE. Results show better consistency between gauges and the two 3B42 products, particularly during warm season months that are associated with high-intensity convective events. All satellite products are shown to have a magnitude-dependent error ranging from overestimation at low precipitation regimes to underestimation at high precipitation accumulations; this effect is more pronounced in the CMORPH and PERSIANN products.

1 November 2014 in Journal of Hydrology
Verified
Journal Article
Closed access
FMFrancesco Marra
Francesco Marra
ENEfthymios Nikolopoulos
Efthymios Nikolopoulos
JCJean Dominique Creutin
Jean Dominique Creutin
MBMarco Borga
Marco Borga

1 August 2015 in Geomorphology
Verified
Journal Article
Closed access
ENEfthymios Nikolopoulos
Efthymios Nikolopoulos
MBMarco Borga
Marco Borga
JCJ.D. Creutin
J.D. Creutin
FMFrancesco Marra
Francesco Marra

7 December 2019 in Remote Sensing
Verified
Journal Article
Open access
PDF file
YDYagmur Derin
Yagmur Derin
EAEmmanouil Anagnostou
Emmanouil Anagnostou
ABAlexis Berne
Alexis Berne
MBMarco Borga
Marco Borga
BBBrice Boudevillain
Brice Boudevillain
KYKoray K. YILMAZ
Koray K. YILMAZ
The great success of the Tropical Rainfall Measuring Mission (TRMM) and its successor Global Precipitation Measurement (GPM) has accelerated the development of global high-resolution satellite-based precipitation products (SPP). However, the quantitative accuracy of SPPs has to be evaluated before using these datasets in water resource applications. This study evaluates the following GPM-era and TRMM-era SPPs based on two years (2014–2015) of reference daily precipitation data from rain gauge networks in ten mountainous regions: Integrated Multi-SatellitE Retrievals for GPM (IMERG, version 05B and version 06B), National Oceanic and Atmospheric Administration (NOAA)/Climate Prediction Center Morphing Method (CMORPH), Global Satellite Mapping of Precipitation (GSMaP), and Multi-Source Weighted-Ensemble Precipitation (MSWEP), which represents a global precipitation data-blending product. The evaluation is performed at daily and annual temporal scales, and at 0.1 deg grid resolution. It is shown that GSMaPV07 surpass the performance of IMERGV06B Final for almost all regions in terms of systematic and random error metrics. The new orographic rainfall classification in the GSMaPV07 algorithm is able to improve the detection of orographic rainfall, the rainfall amounts, and error metrics. Moreover, IMERGV05B showed significantly better performance, capturing the lighter and heavier precipitation values compared to IMERGV06B for almost all regions due to changes conducted to the morphing, where motion vectors are derived using total column water vapor for IMERGV06B.