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Cesar Azorin-Molina  - - - 
Top co-authors See all
E. Cuevas

306 shared publications

Izaña Atmospheric Research Center (IARC), State Meteorological Agency (AEMET), Santa Cruz de Tenerife, Spain

R. M. Trigo

217 shared publications

Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa; Lisboa Portugal

Deliang Chen

184 shared publications

Regional Climate Group, Department of Earth Sciences; University of Gothenburg; Gothenburg Sweden

J. Julio Camarero

179 shared publications

Instituto Pirenaico de Ecología (IPE-CSIC), 50192 Zaragoza, Spain

Shafiqur Rehman

171 shared publications

Centre for Engineering Research; Research Institute, King Fahd University of Petroleum and Minerals; Dhahran 31261 Saudi Arabia

Publication Record
Distribution of Articles published per year 
(2006 - 2018)
Publications See all
Article 0 Reads 1 Citation Evaluating anemometer drift: A statistical approach to correct biases in wind speed measurement Cesar Azorin-Molina, Jesús Asín, Tim R. McVicar, Lorenzo Min... Published: 01 May 2018
Atmospheric Research, doi: 10.1016/j.atmosres.2017.12.010
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Recent studies on observed wind variability have revealed a decline (termed “stilling”) of near-surface wind speed during the last 30–50 years over many mid-latitude terrestrial regions, particularly in the Northern Hemisphere. The well-known impact of cup anemometer drift (i.e., wear on the bearings) on the observed weakening of wind speed has been mentioned as a potential contributor to the declining trend. However, to date, no research has quantified its contribution to stilling based on measurements, which is most likely due to lack of quantification of the ageing effect. In this study, a 3-year field experiment (2014–2016) with 10-minute paired wind speed measurements from one new and one malfunctioned (i.e., old bearings) SEAC SV5 cup anemometer which has been used by the Spanish Meteorological Agency in automatic weather stations since mid-1980s, was developed for assessing for the first time the role of anemometer drift on wind speed measurement. The results showed a statistical significant impact of anemometer drift on wind speed measurements, with the old anemometer measuring lower wind speeds than the new one. Biases show a marked temporal pattern and clear dependency on wind speed, with both weak and strong winds causing significant biases. This pioneering quantification of biases has allowed us to define two regression models that correct up to 37% of the artificial bias in wind speed due to measurement with an old anemometer.
Article 2 Reads 0 Citations Recent trends in wind speed across Saudi Arabia, 1978-2013: a break in the stilling Cesar Azorin-Molina, Shafiqur Rehman, Jose A. Guijarro, Tim ... Published: 29 January 2018
International Journal of Climatology, doi: 10.1002/joc.5423
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We analyse recent trends and variability of observed near-surface wind speed from 19 stations across Saudi Arabia (SA) for 1978–2013. The raw wind speed data set was subject to a robust homogenization protocol, and the stations were then classified under three categories: (1) coast, (2) inland and (3) mountain stations. The results reveal a statistically significant (p < 0.05) reduction of wind speed of −0.058 m s−1 dec−1 at annual scale across SA, with decreases in winter (−0.100 m s−1 dec−1) and spring (−0.066 m s−1 dec−1) also detected, being non-significant in summer and autumn. The coast, inland and mountain series showed similar magnitude and significance of the declining trends across all SA series, except for summer when a decoupled variability and opposite trends of wind speed between the coast and inland series (significant declines: −0.101 m s−1 dec−1 and −0.065 m s−1 dec−1, respectively) and the high-elevation mountain series (significant increase: +0.041 m s−1 dec−1) were observed. Even though wind speed declines dominated across much of the country throughout the year, only a small number of stations showed statistically significant negative trends in summer and autumn. Most interestingly, a break in the stilling was observed in the last 12-year (2002–2013) period (+0.057 m s−1 dec−1; not significant) compared to the significant slowdown detected in the previous 24-year (1978–2001) period (−0.089 m s−1 dec−1). This break in the slowdown of winds, even followed by a non-significant recovery trend, occurred in all seasons (and months) except for some winter months. Atmospheric circulation plays a key role in explaining the variability of winds, with the North Atlantic Oscillation positively affecting the annual wind speed, the Southern Oscillation displaying a significant negative relationship with winds in winter, spring and autumn, and the Eastern Atlantic negatively modulating winds in summer.
Article 4 Reads 2 Citations Wind speed variability over the Canary Islands, 1948–2014: focusing on trend differences at the land–ocean interface and... Cesar Azorin-Molina, Melisa Menéndez, Tim R. McVicar, Adrian... Published: 21 August 2017
Climate Dynamics, doi: 10.1007/s00382-017-3861-0
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This study simultaneously examines wind speed trends at the land–ocean interface, and below–above the trade-wind inversion layer in the Canary Islands and the surrounding Eastern North Atlantic Ocean: a key region for quantifying the variability of trade-winds and its response to large-scale atmospheric circulation changes. Two homogenized data sources are used: (1) observed wind speed from nine land-based stations (1981–2014), including one mountain weather station (Izaña) located above the trade-wind inversion layer; and (2) simulated wind speed from two atmospheric hindcasts over ocean (i.e., SeaWind I at 30 km for 1948–2014; and SeaWind II at 15 km for 1989–2014). The results revealed a widespread significant negative trend of trade-winds over ocean for 1948–2014, whereas no significant trends were detected for 1989–2014. For this recent period wind speed over land and ocean displayed the same multi-decadal variability and a distinct seasonal trend pattern with a strengthening (late spring and summer; significant in May and August) and weakening (winter–spring–autumn; significant in April and September) of trade-winds. Above the inversion layer at Izaña, we found a predominance of significant positive trends, indicating a decoupled variability and opposite wind speed trends when compared to those reported in boundary layer. The analysis of the Trade Wind Index (TWI), the North Atlantic Oscillation Index (NAOI) and the Eastern Atlantic Index (EAI) demonstrated significant correlations with the wind speed variability, revealing that the correlation patterns of the three indices showed a spatio-temporal complementarity in shaping wind speed trends across the Eastern North Atlantic.
Article 0 Reads 0 Citations In situ observations of meteorological variables and snowpack distribution at the Izas Experimental Catchment (Spanish P... Jesús Revuelto, Cesar Azorin-Molina, Esteban Alonso-González... Published: 01 June 2017
Earth System Science Data Discussions, doi: 10.5194/essd-2017-43
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His work describes the snow and meteorological dataset available for the Izas Experimental Catchment, in the Central Spanish Pyrenees, from 2011 to 2016 snow seasons. The experimental site is located in the southern side of the Pyrenees between 2000 and 2300 m above sea level with an extension of 55 ha. The site is a good example of sub-alpine ambient in which snow accumulation and melting dynamics have major importance in many mountain processes. The climatic dataset includes information on different meteorological variables acquired with an Automatic Weather Station (AWS) such as precipitation, air temperature, incoming and reflected short and long-wave radiation, relative humidity, wind speed and direction, atmospheric air pressure, surface temperature (snow or soil surface) and soil temperature; all of them at 10 minute intervals. Snow depth distribution was measured during 23 field campaigns using a Terrestrial Laser Scanner (TLS), and there is also available daily information of the Snow Covered Area (SCA) retrieved from time-lapse photography. The data set ( is valuable since it provides high spatial resolution information on the snow depth and snow cover distribution, which is particularly useful in combination with meteorological variables to simulate the snow energy and mass balance. This information has already been analyzed in different scientific works studying snow pack dynamics and its interaction with the local climatology or terrain topographic characteristics. However, the database generated till the date has great potential for understanding other environmental processes from a hydrometerological or ecological perspective in which snow dynamics play a determinant role.
Article 5 Reads 7 Citations Diverse relationships between forest growth and the Normalized Difference Vegetation Index at a global scale Sergio M. Vicente-Serrano, J. Julio Camarero, José Miguel Ol... Published: 01 December 2016
Remote Sensing of Environment, doi: 10.1016/j.rse.2016.10.001
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Article 2 Reads 8 Citations Homogenization and assessment of observed near-surface wind speed trends across Sweden, 1956-2013 Lorenzo Minola, Cesar Azorin-Molina, Deliang Chen Published: 01 October 2016
Journal of Climate, doi: 10.1175/jcli-d-15-0636.1
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