Nicolau Pineda

Nicolau Pineda
Servei Meteorològic de Catalunya · Remote Sensing Unit

PhD, Remote Sensing

About

134
Publications
19,922
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1,427
Citations
Citations since 2017
50 Research Items
969 Citations
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2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250

Publications

Publications (134)
Preprint
Full-text available
Holdover fires are usually associated with lightning-ignited wildfires (LIWs), which can experience a smouldering phase or go undetected for several hours to days and weeks before being reported. Since the existence and duration of the smouldering combustion in LIWs is usually unknown, holdover time is conventionally defined as the time between the...
Data
This database contains open, harmonized, and ready-to-use global data on holdover time. Holdover time is defined as the time between lightning-induced fire ignition and fire detection. The first version of the database is composed of three data files (censored data, non-censored data, ancillary data) and three metadata files (description of databas...
Article
Este artículo repasa la investigación sobre la teledetección y meteorología de los incendios de rayo llevada a cabo por el Servei Meteorològic de Catalunya (meteo.cat), en colaboración con el Lightning Research Group de la Universidad Politécnica de Catalunya, en los últimos 10 años. El conjunto de resultados obtenidos hasta la fecha ha de servir p...
Conference Paper
Winter storm Filomena battered the Iberian Peninsula on the 9-10th January 2021, covering the eastern half of Spain with a huge amount of snow. Apart from the historical snowfall, lightning activity was observed during this snowstorm episode. Although most of lightning was oversea, lightning hotspots were observed in different regions across the Ib...
Article
In the present work, we analysed fuel moisture conditions during ignition, holdover, and detection of flaming combustion of lightning-ignited wildfires in Catalonia (north-eastern Spain) between 2003 and 2018. First, we identified the most probable lightning candidate for each wildfire, implementing a matching algorithm between historical lightning...
Article
Full-text available
Wildfires cause substantial losses to socio-economic and natural assets, especially in Mediterranean climate regions. Despite human activity being the main cause of wildfires in Mediterranean European countries, lightning-ignited wildfires should also be considered a major disruptive agent as they can trigger large fires. In addition, recent studie...
Article
Full-text available
Lightning is the major cause of natural ignition of wildfires worldwide and produces the largest wildfires in some regions. Lightning strokes produce about 5% of forest fires in the Mediterranean basin and are one of the most important precursors of the largest forest fires during the summer. Lightning-ignited wildfires produce significant emission...
Article
This work studies the characteristics of thunderstorms that cause lightning-caused wildfires in Catalonia, north-east Iberian Peninsula, using lightning and weather radar data. Although thunderstorms produce ~57 000 cloud-to-ground (CG) flashes yearly in Catalonia, only 1 in 1000 end up as a flaming wildfire. Characterisation of thunderstorms that...
Article
Full-text available
Heavy snowfall events can cause substantial transport disruption and exert a negative socio‐economic impact, particularly in low altitude and mid‐latitude regions where it seldom snows. Such problems may be exacerbated if there are rapid transitions between different precipitation phases within the same event. Previous studies have addressed this i...
Article
Full-text available
The Atmosphere-Space Interactions Monitor (ASIM) on the International Space Station (ISS) provides optical radiances and images of lightning flashes in several spectral bands. This work presents a lightning flash simultaneously observed from space by ASIM, the Geostationary Lightning Mapper (GLM) and the Lightning Imaging Sensor on the Internationa...
Preprint
Full-text available
Lightning is the major cause of natural ignition of wildfires worldwide and produces the largest wildfires in some regions. Lightning strokes produce about 5 % of forest fires in the Mediterranean basin and are one of the most important precursors of the largest forest fires during the summer. Lightning-ignited wildfires produce significant emissio...
Article
Thunderstorm electrical structures favouring cloud-to-ground lightning were investigated through a Lightning Mapping Array (LMA), an accurate three-dimensional lightning location system that allows inferring the heights of the regions of charge. The present study focused on classical, convective-scale thunderstorms, aiming to shed new light on how...
Article
Surface precipitation phase (SPP) discrimination at the ground level (rain or snow) is a key step in numerous meteorological and hydrological applications. Previous studies have undertaken this by comparing surface observations, such as air temperature, relative humidity and wet-bulb temperature, with concurrent present weather observations of the...
Article
In this paper, we analyze meteorological conditions, thundercloud structure, lightning activity and characteristics of the flashes that strike two towers separated by 1.3 km on Tosa d'Alp (2537 m asl) for two days (March 24 and 31) of the Cerdanya-2017 field campaign. Remote sensing products (cloud top temperature, lightning flash location, volumet...
Article
We investigated features of corona point discharges when a grounded conductive rod is subject to a high background electric field. In the laboratory, high voltage is applied to an upper plate in a plane-to-point experiment, and the discharges are observed from a grounded rod using an ultraviolet camera and a photosensor. The current is measured usi...
Article
An adaptive high-temporal resolution interpolation scheme for meteorological observations is presented. It stems from a combination of linear regression, anomaly correction and clustering. A number of approaches to tackle this problem for monthly and daily data have been proposed in the past, but interpolation studies at sub-daily temporal scales a...
Article
Lightning Location Systems provide detailed data on the lightning occurring within the area of the system's coverage. This kind of remote sensing equipment uses geolocation techniques to retrieve lightning cloud-to-ground return strokes. Prior to getting information regarding the number of lightning flashes, cloud-to-ground strokes need to be group...
Article
Given the growing concern on lightning threats outside the main warm-season, the objective of this study is to get further insight on the seasonal variations of the necessary conditions required for the production of lightning. In this regard, the study aims to find a basic indicator of cloud electrification that could be useful as an all-year-roun...
Article
Full-text available
Interest in exploring the meteorological conditions favoring upward lightning from tall man‐made structures has grown in recent years, largely due to the worldwide expansion of wind energy. To this end, instrumented towers existing around the world are the most suitable places to study upward lightning. In this context, an LMA network was deployed...
Article
We present in this paper lightning current measurements, LMA (Lightning Mapping Array) data and fast antenna electric fields associated with upward flashes observed at the Säntis Tower during summer of 2017. The LMA network consists of six stations that were installed in the vicinity of the tower at distances ranging from 100 m to 11 km from it. Ou...
Presentation
Full-text available
In this study, an attempt is made to identify severe weather patterns that may be useful for the recognition of tornados embedded in mesoscale convective systems or squall lines. Weak tornados are frequent in southern Europe and near the Mediterranean coastal regions in particular, mostly during late summer and early autumn. In particular, the anal...
Article
Full-text available
This paper presents an analysis of the lightning production of convective cells. The cells were detected by the MeteoSwiss Thunderstorms Radar Tracking (TRT) algorithm in the course of a lightning measurement campaign that took place in the summer of 2017 in the area surrounding the Säntis mountain, in the northeastern part of Switzerland. For this...
Article
The 15 January 2017 a strong northerly synoptic flow lead to the generation of mountain waves and heavy snowfall over the eastern Pyrenees, particularly over the Cerdanya valley near the border between France, Spain and Andorra. Measurements from several instruments deployed during the Cerdanya-2017 field campaign and satellite imagery revealed the...
Article
Full-text available
Africa is one of the most productive lightning regions on Earth, yet it has a lower terrestrial gamma ray flash (TGF)‐to‐lightning ratio especially compared with Central America. In this paper, we have analyzed the global distribution of different meteorological parameters in order to explain the TGF/lightning ratio asymmetry. We show here that a d...
Article
Full-text available
Charge structure derived from lightning leader development of tropical thunderstorms comprising equatorial latitudes of less than ±10° has not been investigated yet. In this work, using a lightning mapping array installed in northern Colombia, the charge structure, lightning leader initiations, and the cloud‐to‐ground strokes rates of two thunderst...
Article
Full-text available
In this paper we present an analysis of a large dataset of lightning and polarimetric weather radar data collected in the course of a lightning measurement campaign that took place in the summer of 2017 in the area surrounding Säntis, in the northeastern part of Switzerland. For this campaign and for the first time in the Alps, a lightning mapping...
Article
Full-text available
This paper presents an analysis of the lightning production of convective cells. The cells were detected by the MeteoSwiss Thunderstorms Radar Tracking (TRT) algorithm in the course of a lightning measurement campaign that took place in the summer of 2017 in the area surrounding the Säntis mountain, in the northeastern part of Switzerland. For this...
Presentation
Full-text available
The 18 October 2017 a severe thunderstorm affected Catalonia (NE Spain), an area where tornadic events are regularly reported, with 5 tornadoes/year during the 2000 to 2016 period as described by Rodriguez and Bech (2018). This particular event hit the city of Valls causing 13 injured people and damaging 30 lamp posts, 100 traffic signs and over 27...
Conference Paper
The 18 October 2017 a severe thunderstorm affected Catalonia (NE Spain), an area where tornadic events are regularly reported, with 5 tornadoes/year during the 2000 to 2016 period as described by Rodriguez and Bech (2017). This particular event hit the city of Valls causing 13 injured people and damaging 30 lampposts, 100 traffic signs and over 270...
Article
Full-text available
Southern European countries rely largely on fire suppression and ignition prevention to manage a growing wildfire problem. We explored a more wholistic, long-term approach based on priority maps for the implementation of diverse management options aimed at creating fire resilient landscapes, restoring cultural fire regimes, facilitating safe and ef...
Article
Full-text available
In this paper we present an analysis of a large dataset of lightning and polarimetric weather radar data collected in the course of a lightning measurement campaign that took place in the summer of 2017 in the area surrounding the Säntis mountain, in the northeastern part of Switzerland. For this campaign, and for the first time in the Alps, a ligh...
Conference Paper
We present in this paper lightning current measurements and LMA (Lightning Mapping Array) data associated with upward flashes observed at the Säntis Tower during Summer 2017. The LMA network consists of six stations located in the vicinity of the tower at distances ranging from 100 m to 11 km from it. 20 flashes simultaneously recorded by the curre...
Presentation
Full-text available
Severe thunderstorms producing large hail, heavy rainfall and strong winds from convective origin, occur frequently in southern Europe and near the Mediterranean coastal regions in particular, mostly during late summer and early autumn. For example over the period 2000 to 2016 a yearly average of 5 tornadoes, mostly weak (<EF2) were reported in Cat...
Article
Meteorological conditions and thunderstorm characteristics related to lightning threats to wind turbines are discussed in this paper. Due to the rotating blades, wind turbines may be regarded peculiar tall objects, more susceptible to lightning strikes than other tall man-made structures. In the present study, Lightning Mapping Array and weather ra...
Article
Severe weather regularly hits the Lleida Plain (western part of Catalonia, NE of Iberian Peninsula), causing important damage to the local agriculture. In order to help severe weather surveillance tasks, the Meteorological Service of Catalonia (SMC) implemented in 2016 the Lightning Jump (LJ) algorithm as operative warning tool after an exhaustive...
Article
3D mapping system like the LMA - Lightning Mapping Array - are a leap forward in lightning observation. LMA measurements has lead to an improvement on the analysis of the fine structure of lightning, allowing to characterize the duration and maximum extension of the cloud fraction of a lightning flash. During several years of operation, the first L...
Conference Paper
Full-text available
Nowcasting tools based on weather radar present as main advantage the robustness at the time of identify correctly thunderstorms, and, moreover, to estimate the path in the past. These facts allow a correct forecasting of the future trajectories, or, at least, to identify anomalous trajectories of the convective cells. However, it is especially dif...
Conference Paper
Full-text available
Farnell et al (2017) put in operational a Lightning Jump (LJ) algorithm intended for nowcasting and surveillance of severe weather. The good results obtained in the off-line validation (with more than 140 episodes from the period between 2006 and 2013), lead to an operative implementation at the Meteorological Service of Catalonia. The 2016 campaig...
Conference Paper
Full-text available
The Lightning Jump algorithm has shown to be a good tool for the nowcasting of severe weather. The algorithm is currently an operational tool at the Meteorological Service of Catalonia. Going deeper into the relationship between hailstorms and the lightning jump pattern, the present study analyses the characteristics and behaviour of the convective...
Article
Wildland fires originated by lightning in Catalonia (NE Spain) are systematically examined through theuse of lightning and precipitation data. The region of study, with a Mediterranean climate, is prone tosummer wildfires. Despite being mainly anthropogenic, lightning-ignited fires (10%) are relevant as theycan trigger large fires. Given that the l...
Article
In Doppler weather radars, the presence of unfolding errors or outliers is a well-known quality issue for radial velocity fields estimated using the dual-Pulse Repetition Frequency (PRF) technique. Post-processing methods have been developed to correct dual-PRF outliers but these need prior application of a dealiasing algorithm for an adequate corr...
Article
Several studies reported sudden increases in the total lightning flash rate (intra-cloud+cloud-to-ground) preceding the occurrence of severe weather (large hail, wind gusts associated to thunderstorms and/or tornadoes). Named “Lightning Jump”, this pattern has demonstrated to be of operational applicability in the forecasting of severe weather phen...
Article
On 29-30 October 2013, a low-light video camera installed at Pic du Midi (2877m), recorded transient luminous events above a very active storm over the Mediterranean Sea. The minimum cloud top temperature reached -73°C, while its cloud to ground (CG) flash rate exceeded 30flmin⁻¹. Some sprite events have long duration and resemble to dancing sprite...
Poster
Full-text available
According to existing records, Catalonia (NE of the Iberian Peninsula, in the Western Mediterranean sea), is one of the most tornado-prone regions in Spain, with an average of 3 tornadoes per year during the period 1980 to 2009, being most of them weak – 87% F0 and F1 in the Fujita scale, and the rest F2. Most tornadoes occur from July to early Nov...
Conference Paper
Full-text available
The paper presents winter lightning maps on specific regions in the northern hemisphere. Four different degrees of winter lightning activity are defined based on information derived from Japanese case. Based on this reference case it is possible to determine regions where winter lightning can be a threat to specific structures. Guidance on risk ass...
Article
The present study makes use of cloud-to-ground lightning, three-dimensional mapping from a Lightning Mapping Array and Doppler C-band radar observations to analyze the lightning trends and the underlying electrical charge structure of a large-hail bearing storm that produced important damages on the local agriculture. The analysis reported an extre...
Conference Paper
Negative downward leaders that produced lightning strokes to wind turbines are identified by means of the Lightning Mapping Array data of the Ebro Valley Laboratory (NE Spain). Four cases are analyzed together with weather radar imagery. All flashes hitting wind turbines were originated in small convective cells with moderate development. Notwithst...
Article
The analysis of high-energy background radiation (0.1-2MeV) enhancements during eight winter thunderstorms and five summer storms in the Ebro delta region in the northeast of Spain is presented. For the first time, high-energy radiation counts, precipitation, radar reflectivity and very high frequency lightning detections to infer charge regions al...
Article
Full-text available
Lightning is one of the major threats to multi-megawatt wind turbines and a concern for modern aircraft due to the use of lightweight composite materials. Both wind turbines and aircraft can initiate lightning, and very favorable conditions for lightning initiation occur in winter thunderstorms. Moreover, winter thunderstorms are characterized by a...
Article
Full-text available
Lightning is one of the major threats to multi-megawatt wind turbines and a concern for new generation of aircraft. That is because the use of lightweight of some composite materials. Both wind turbines and aircraft can initiate lightning and very favourable conditions for lightning initiation occur in winter thunderstorms. Moreover, winter thunder...
Article
Full-text available
Three methods for estimation of the weather radar antenna azimuth and elevation pointing offsets are compared. Two of the methods reviewed use the known location of the sun as a reference. The first of these methods is based on an offline scan of the sun disk. The second method detects and characterizes solar interferences in operative scans. The t...
Article
Full-text available
This study analyzes a long-lived thunderstorm with supercell characteristics that took place in the northeastern Iberian Peninsula on 5 July 2012. Severe weather features identified in Doppler radar and total lightning data have been used to infer the severity of this large-hail-bearing storm that substantially damaged local agriculture. Key elemen...
Conference Paper
Full-text available
The main goal of this study is the characterization of the thunderstorm patterns in Catalonia through their lightning activity. Principal Component Analysis (PCA) has been used to regionalize Catalonia (NE Iberian Peninsula) and characterize the main features of each region, based on ten-years of lightning activity recorded by the Lightning Locatio...
Conference Paper
Full-text available
Different sources of information related to severe weather are available in Catalonia (NE Iberian Peninsula), giving actual observations (e.g wind gusts) or indirect data potentially useful as proxy data. The 170 Automatic Weather Stations network of the Meteorological Service of Catalonia (SMC) provide local observations of strong wind gusts A net...
Article
Lightning current parameters derived from Lightning Location Systems (LLS) have been used in the past to assess their influence in the local performance of the Network. The paper presents an analysis of the statistical parameters for negative peak current strokes and flashes in different areas of Catalonia (32 000 km2) for two different LLS operati...
Article
Full-text available
35 sprite-producing lightning flashes were recorded in 9 nights in different seasons at the east coast of Spain with a 3D Lightning Mapping Array (LMA) since July 2011. A low-frequency time-of-arrival network provided data on emissions from return strokes and intracloud processes and a very-high-frequency interferometer network produced complementa...
Article
This study presents a description of a quasi linear convective system that took place in Catalonia (NE Spain) on 21 March 2012 producing heavy rainfall, moderate lightning activity and a weak tornado in the village of Ivars d’Urgell around 19 UTC after local sunset. A post-event survey indicated EF0 and EF1 damage in houses of the village –roofs an...
Conference Paper
Full-text available
Using a data base of events that have affected an agricultural area of Catalonia between 2004 and 2012, and geo-statistical analysis, the main goal of the study is the evaluation of correlations between the number of lightning flashes (cloud-to-ground or intra-cloud) closed to hail diameter observations at surface provided by a 170 hail-pad network...
Conference Paper
Full-text available
32 sprite-producing lightning flashes were recorded in 8 nights in different seasons at the east coast of Spain with a 3D Lightning Mapping Array (LMA), operational since July 2011. The bidirectional development of flashes is analyzed using the time-distance method of van der Velde and Montanyà (2013) in order to explain the positioning and timing...
Conference Paper
In this paper we present the evolution of a bidirectional leader which appeared in ‘virgin’ air. In the observations we did not find any delay between the onsets of the two leader ends. The positive leader end presented a single channel, brighter and slower than the negative end. On the other side, the negative end was branched, less bright and twi...
Conference Paper
The size and duration of lightning flashes are examined. Data from the Ebro Valley Laboratory Lightning Mapping Array is used as reference. Additional data from the VLF/LF LINET network is included. In the analysis, each flash is simplified by a confidence ellipse fitting most of the detected sources. The major axis of the ellipse is adopted as the...
Article
Full-text available
[1] Electric fields and high energy radiation of natural lightning measured at close range from a mountain-top tower are discussed. In none of the twelve negative cloud-to-ground upward flashes (upward positive leaders) were X-rays observed. Also no energetic radiation was found in one negative upward leader at close range (20 m). In the first of t...
Conference Paper
Full-text available
Single‐polarization weather radar precipitation estimates present an inherent ambiguity regarding the observed hydrometeor type. In the past, different methodologies have been developed to overcome this limitation. We used as starting point earlier studies carried out in northern Europe which combined single polarization weather radar observations...
Conference Paper
In recent years, research of transient luminous events is shifting from the rather common elves and sprites high above thunderclouds to the much less frequently observed phenomena issued by the storm cloud itself: gigantic jets (GJ) connecting to the ionosphere, and high-energy terrestrial gamma-ray flashes (TGFs) recorded at spacecraft. These phen...
Article
This paper summarizes results obtained by the 2009–2010 field campaigns conducted in northeastern Spain using a high speed camera, VHF interferometer, VLF lightning location system and scintillation detectors for energetic radiation. The main purpose was to obtain new insight into the lightning processes which emit x/γ radiation. For just one (very...
Conference Paper
Full-text available
Fog is very important from several perspectives: as a hazard to traffic at land, at sea and for aviation, as a factor with an impact on air quality, and as a modifier in the climate system. In Catalonia (NE Spain), some areas are strongly affected by the presence of fog mainly during autumn and winter, with the corresponding impact on traffic manag...