Malcolm Haylock's research while affiliated with University of East Anglia and other places

Publications (39)

Article
Rain gauges provide valuable information about the amount and frequency of rainfall. In Australia, the majority of rain gauges are located in populated, wet coastal regions. Approximately 2000 gauges reporting within 24 h of a target day were used to make near real-time (NRT) estimates of daily precipitation. The remaining ≈4000 gauges for the same...
Article
Daily precipitation observations are commonly used with related variables to make estimates at unsampled locations to provide maps and gridded data for hydrological and climate model applications. Uncertainty in the way gridded data (maps) are prepared, given the available information, is rarely considered. Over a study period of one year, we used...
Article
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The Climatic Research Unit (CRU) is widely recognised as one of the world's leading institutions concerned with the study of natural and anthropogenic climate change. CRU is part of the School of Environmental Sciences at the University of East Anglia in Norwich. The aim of the Climatic Research Unit is to improve scientific understanding in three...
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Uncertainty in the return levels of insured loss from European wind storms was quantified using storms derived from twenty-two 25 km regional climate model runs driven by either the ERA40 reanalyses or one of four coupled atmosphere-ocean global climate models. Storms were identified using a model-dependent storm severity index based on daily maxim...
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Gridded data sets derived through interpolation of station data have a number of potential inaccuracies and errors. These errors can be introduced either by the propagation of errors in the station data into derived gridded data or by limitations in the ability of the interpolation method to estimate grid values from the underlying station network....
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This study presents a systematic evaluation of the homogeneity of daily surface temperature observations for the Caribbean and neighbouring regions on a monthly timescale. The reference series are developed using adjacent sea surface temperatures (SSTs). This novel approach is undertaken instead of the conventional use of highly correlated nearby s...
Article
We compare versions of six interpolation methods for the interpolation of daily precipitation, mean, minimum and maximum temperature, and sea level pressure from station data over Europe from 1961 to 1990. The interpolation methods evaluated are global and local kriging, two versions of angular distance weighting, natural neighbor interpolation, re...
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We present a European land-only daily high-resolution gridded data set for precipitation and minimum, maximum, and mean surface temperature for the period 1950–2006. This data set improves on previous products in its spatial resolution and extent, time period, number of contributing stations, and attention to finding the most appropriate method for...
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In this study we introduce a daily high-resolution land-only observational gridded data set for sea level pressure covering the European region as a new addition to the E-OBS gridded data sets of daily temperatures and precipitation amounts. This data set improves upon existing products in terms of spatial resolution and extent. The data set is del...
Article
5 [1] We analyzed a new data set of 54 high-quality homogenized daily maximum 6 temperature series from Western Europe to define more accurately the change in extreme 7 warm Daily Summer Maximum Temperature (DSMT). Results from the daily temperature 8 homogeneity analysis suggest that many instrumental measurements in the late 19th 9 and early 20th...
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Decadal changes in correlations between boreal winter averages of indices of the North Atlantic Oscillation (NAO) and average temperature north of 20°N (NH20N) have been reported in the literature. We show that such fluctuations are caused by changing midfrequency and high-frequency correlations (periods less than 30 years) and are not the result o...
Article
Artificial neural networks have proved an attractive approach to non-linear regression problems arising in environmental modelling, such as statistical downscaling, short-term forecasting of atmospheric pollutant concentrations and rainfall run-off modelling. However, environmental datasets are frequently very noisy and characterized by a noise pro...
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1] This paper compares six statistical downscaling models (SDMs) and three regional climate models (RCMs) in their ability to downscale daily precipitation statistics in a region of complex topography. The six SDMs include regression methods, weather typing methods, a conditional weather generator, and a bias correction and spatial disaggregation a...
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El Niño–Southern Oscillation (ENSO) in a century-long integration of a Bureau of Meteorology Research Centre (BMRC) coupled general circulation model (CGCM) drives rainfall and temperature changes over Australia that are generally consistent with documented observational changes: dry/hot conditions occur more frequently during El Niño years and wet...
Article
Six statistical and two dynamical downscaling models were compared with regard to their ability to downscale seven seasonal indices of heavy precipitation for two station networks in northwest and southeast England. The skill among the eight downscaling models was high for those indices and seasons that had greater spatial coherence. Generally, win...
Article
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A weeklong workshop in Brazil in August 2004 provided the opportunity for 28 scientists from southern South America to examine daily rainfall observations to determine changes in both total and extreme rainfall. Twelve annual indices of daily rainfall were calculated over the period 1960 to 2000, examining changes to both the entire distribution as...
Article
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A suite of climate change indices derived from daily temperature and precipitation data, with a primary focus on extreme events, were computed and analyzed. By setting an exact formula for each index and using specially designed software, analyses done in different countries have been combined seamlessly. This has enabled the presentation of the mo...
Conference Paper
Artificial neural networks have proved an attractive approach to non-linear regression problems arising in environmental modelling, such as statistical downscaling, short-term forecasting of atmospheric pollutant concentrations and rainfall run-off modelling. However, environmental datasets are frequently very noisy and characterised by a noise pro...
Conference Paper
Artificial neural networks have proved an attractive approach to non-linear regression problems arising in environmental modelling, such as statistical downscaling, short-term forecasting of atmospheric pollutant concentrations and rainfall run-off modelling. However, environmental datasets are frequently very noisy and characterised by a noise pro...
Conference Paper
Full-text available
A weeklong workshop in Brazil in August 2004 provided the opportunity for 28 scientists from southern South America to examine daily rainfall observations to determine changes in both total and extreme rainfall. Twelve annual indices of daily rainfall were calculated over the period 1960 to 2000, examining changes to both the entire distribution as...
Article
Full-text available
A workshop on enhancing climate change indices in South America was held in Maccio. Brazil, in August 2004. Scientists from eight southern countries brought daily climalological data from their region for a meticulous assessment of data quality and homogeneity, and for the preparation of climate change indices that can be used for analyses of chang...
Article
The numbers of warm nights and hot days, across most of the east Asia - west Pacific region, increase substantially in the year after the onset of an El Niño event. The number of cool days and cold nights tend to decrease, although the relationship with El Niño is weaker for these variables. The relationship is confounded, for warm nights and hot d...
Article
Trends (1961–2003) in daily maximum and minimum temperatures, extremes and variance were found to be spatially coherent across the Asia–Pacific region. The majority of stations exhibited significant trends: increases in mean maximum and mean minimum temperature, decreases in cold nights and cool days, and increases in warm nights. No station showed...
Article
December–February (DJF) extreme rainfall was analysed at 347 European stations for the period 1958–2000. Two indices of extreme rainfall were examined: the maximum number of consecutive dry days (CDD); and the number of days above the 1961–90 90th percentile of wet-day amounts (R90N). A principal component analysis of CDD found six components that...
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Various earlier studies have demonstrated that rainfall in the Maritime Continent-Indonesia region is strongly related to the El Nino-Southern Oscillation (ENSO) during the dry half of the year but has a very weak association with ENSO during the summer-wet season months. This relationship is investigated over a wider domain through the use of outg...
Article
STARDEX will provide a rigorous and systematic inter-comparison and evaluation of statistical and dynamical downscaling methods for the construction of scenarios of extremes. The more robust techniques will be identified and used to produce scenarios for European case-study regions for the end of the 21st century. During the first year of the proje...
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A new global dataset of derived indicators has been compiled to clarify whether frequency and/or severity of climatic extremes changed during the second half of the 20th century, This period provides the best spatial coverage of homogenous daily series, which can be used for calculating the proportion of global land area exhibiting a significant ch...
Article
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Rainfall from 63 stations across Indonesia is examined for the period 1950-98 to determine the spatial coherence of wet season anomalies. An example of almost unrelated anomalies at two neighboring stations is presented. Principal component analysis is used to quantify the spatial coherence across the entire region. The significant components show...
Article
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Trends in extreme daily temperature and rainfall have been analysed from 1961 to 1998 for Southeast Asia and the South Pacific. This 38-year period was chosen to optimize data availability across the region. Using high-quality data from 91 stations in 15 countries, significant increases were detected in the annual number of hot days and warm nights...
Article
Daily rainfall was analysed at 91 high quality stations over eastern and southwestern Australia to determine if extreme rainfall had changed between 1910 and 1998. Three indices of extreme rainfall were examined: the number of events above an extreme threshold (extreme frequency); the average intensity of rainfall from extreme events (extreme inten...
Article
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Dissemination Level PU Public X PP Restricted to other programme participants (including the Commission Services) RE Restricted to a group specified by the consortium (including the Commission Services) CO Confidential, only for members of the Consortium (including the Commission Services) Abstract Daily gridded data are needed for the validation o...

Citations

... In recent decades, the global climate has changed significantly, and the most prominent feature is that the global climate shows a warming trend [6]. The frequency and intensity of extreme precipitation events increase significantly in the context of global warming [7]. In the case of global warming, the response of extreme precipitation to temperature in China remains to be discussed. ...
... Regionally and seasonally, the magnitude of the trends is most notable in the Central Great Plains, northern Midwest and eastern two-thirds of the country in opposition to an increasing dryness in the interior west and southwest; and primarily in the warm season (Pryor et al., 2009). While South America has generally became wetter as the total precipitation, average rainfall intensity, extreme rainfall events and the length of consecutive wet days all are on an increasing mode, Southern Peru, Southern Chile and South-west Argentina are showing drying symptoms (Haylock et al., 2006). Though total precipitation has decreased across the African continent with increasing length of consecutive dry days and decreasing length of consecutive wet days, average rainfall intensity and extreme rainfall events have decreased in western central Africa (Aguilar et al., 2009) while they have increased in Southern Africa (New et al., 2006). ...
... The gamma distribution has been fitted to rainfall amounts in a number of studies 258Stephenson et al. 1999; Giorgi et al. 2001; Yang et al. 2005)Stephenson et al. 1999; Giorgi et al. 2001; Yang et al. 2005)Figure 2)Haylock et al. 2006; Cawley et al. 2007; Cannon 2008): In a second validation approach, several precipitation indices defined inTable 3Table 4Figure 8. The BMAR adequately simulates these joint probabilities 496 and outperforms both hybrid and MMLR models that provide overestimates of these 497 probabilities. ...
... Many applications of neural networks on the implementation of logic rules have been reported (see e.g. Abdelbar, Andrews, & Wunsch, 2005; Altug, Chow, & Trussell, 1999; Cawley, Janacek, Heylock, & Dorling, 2007; Ferraro, Via, Ausiello, & HelmerCitterich, 2005; Goel & Ramanujam, 1997; Gust & Kühnberger, 2005; Hitzler, Holldobler, & Seda, 2004; Lawrence, Giles, & Fong, 2000; Lin & Lee, 1991; Mitra & Pal, 1994; Specht, 1990). In these E-mail address: sun_jianye@yahoo.com. ...
... Some other scholars use more abundant indices, such as quantiles, median, maximum value, and minimum value, for evaluation (Wetterhall et al. 2006). In this study, we selected nine indices categorized into three types, which originated from the European Union STARDEX project (STAtistical and Regional dynamical Downscaling of EXtremes for the European region) (Goodess et al. 2012). In daily scale evaluation, we reserved standard deviation (SD) and 99th percentile of rain day amounts (Pq99) as extra indices. ...
... Furthermore, the Indonesian seas are a prime location of atmospheric convection that drives the Walker Circulation. Hence any changes in sea surface temperature (SST) within these regions will have global impacts on weather and climate events, e.g., [4][5][6]. Ocean mixing in the Indonesian seas affects the mean state of the Indo-Pacific region and its interannual variability [7]. ...
... On the other hand, in our current study, only the linear component related to ENSO is removed. Some previous studies have noticed asymmetry in the Australian rainfall response to ENSO (Power et al. 2005;Cai et al. 2010), which may exert influence on the NWARI-related teleconnection. However, those are beyond the current study. ...
... Additionally, positive trends in extreme rainfall have been observed over southeastern South America (Re and Barros 2009;Penalba and Robledo 2010;Doyle et al. 2012;Donat et al. 2013;Zandonadi et al. 2016;Cerón et al. 2021), while decreasing trends were found over other South American sectors such as the subtropical Andes (Garreaud et al. 2020;Rivera et al. 2021) or southern Chile and southern Peru (Haylock et al. 2006). Naturally, the challenging question in this regard is whether these trends will persist exacerbating or not in the upcoming decades. ...
... The assessment of the different approaches focuses on the analysis of the complete warm season 2009/2010 and each 3-day extreme event selected as case-study. The skill of downscaling is evaluated following the recommendations developed within former international collaborative initiatives, VALUE-COST Action (Maraun et al. 2015) and STARDEX (Goodess et al. 2003), in order to normalize comparisons among different regions of the world. For the 2009/2010 warm season, different indices are considered to evaluate daily precipitation occurrence and amount, such as: relative frequency of wet days (R01), mean wet-day precipitation (SDII, Simple Daily Intensity Index), relative frequency of days with precipitation above 10 mm (R10) and 20 mm (R20) and total precipitation amount (PRCTOT). ...
... e North Atlantic Oscillation (NAO) is the continuous fluctuation of the sea level pressure (SLP) field in the North Atlantic, which can be related to the interannual variation of the pressure over the Azores and Iceland. It represents large-scale alterations in the SLP differences between the subtropical and subpolar regions of the North Atlantic [1]. As the dominant variability mode of the atmospheric circulation in the northern hemisphere, the NAO is the result of complex nonlinear interactions between many spatiotemporal scales [2]. ...