pinecone/core-2020-05-10-deduplication huggingface dataset:
The relationship between built-up areas and the spatial development of the mean maximum urban heat island in Debrecen, Hungary

The climate of built-up regions differs significantly from rural regions and the most important modifying effect of urbanization on local climate is the urban temperature excess, otherwise called the urban heat island (UHI). This study examines the influence of built-up areas on the near-surface air temperature field in the case of the medium-sized city of Debrecen, Hungary. Mobile measurements were used under different weather conditions between March 2002 and March 2003. Efforts concentrated on the determination of the spatial distribution of mean maximum UHI intensity with special regard to land-use features such as built-up ratio and its areal extensions. In both (heating and non-heating) seasons the spatial distribution of the UHI intensity field showed a basically concentric shape with local anomalies. The mean maximum UHI intensity reaches more than 2.0 degrees C (heating season) and 2.5 degrees C (non-heating season) in the centre of the city. We established the relationship between the above-mentioned land-use parameters and mean maximum UHI intensity by means of multiple linear regression analysis. As the measured and predicted mean maximum UHI intensity patterns show, there is an obvious connection between the spatial distribution of urban thermal excess and the land-use parameters examined, so these parameters play a significant role in the development of the strong, UHI intensity field over the city. Copyright (c) 2005 Royal Meteorological Society
Encouraging Use of Seasonal Climate Forecasts by Farmers

What encourages use of seasonal climate forecasts? Considerable effort is being applied in developing seasonal climate forecasts and demonstrating the potential benefits available to farmers from using seasonal climate forecasts. This study examines three factors underlying the use of seasonal climate forecasts by farmers: the level of forecast understanding by farmers, the format presentation of the forecasts, and the attitude of farmers towards the usefulness of forecasts as indicators of future rainfall. Using judgement analysis, the use of forecasts in cropping decisions was determined for 73 Australian farmers. Then a moderated regression analysis was used to predict forecast use from the three underlying factors. The study found that a good understanding of the forecast was more important than the forecast format in predicting its use. However, this main effect of good understanding on higher use was qualified by a three-way interaction, such that seasonal climate forecasts and the forecasts were presented in a frequency format. Thus, the study found all three factors were important in predicting the use of seasonal climate forecasts by farmers. However, relatively little is known about farmer attitudes toward the usefulness of seasonal climate forecasts and how these attitudes arise, and further research is recommended in these areas
The Meteorological Data of William Hutchinson and a Liverpool Air Pressure Time Series Spanning 1768-1999

This paper discusses some of the meteorological measurements made at Liverpool by Captain William Hutchinson in the second half of the 18th century. It gives an overview of the various data sets, most of which are now in computer-accessible form, and provides assessments of their quality, the aim being to gain an overall impression of how good an observer Hutchinson was. His air pressure data have been studied in detail, through comparisons to information from other UK stations, and via investigation of the sea level response to air pressure change as observed in his own tidal measurements. A first attempt has been made to construct a Liverpool air pressure time series spanning 1768-1999, by means of combination of Hutchinson’s data with later information from the Liverpool docks and Bidston Observatory
Interannual variability of the Tropical Atlantic independent of and associated with ENSO: Part II. The South Tropical Atlantic

Two dominant ocean-atmosphere modes of variability on interannual timescales were defined in Part I of this work, namely, the North Tropical Atlantic (NTA) and South Tropical Atlantic (STA) modes. In this paper we focus on the STA mode that covers the equatorial and sub-tropical South Atlantic. We show that STA events occurring in conjunction with ENSO have a preference for the southern summer season and seem to be forced by an atmospheric wave train emanating from the central tropical Pacific and travelling via South America, in addition to the more direct ENSO-induced change in the Walker circulation. They are lagged by one season from the peak of ENSO. These events show little evidence for other-than-localised coupled ocean-atmosphere interaction. In contrast, STA events occurring in the absence of ENSO favour the southern winter season. They appear to be triggered by a Southern Hemisphere wave train emanating from the Pacific sector, and then exhibit features of a self-sustaining climate mode in the tropical Atlantic. The southward shift of the inter tropical convergence zone that occurs during the warm phase of such an event triggers an extra tropical wave train that propagates downstream in the Southern Hemisphere. We present a unified view of the NTA and STA modes through our observational analysis of the interannnual tropical Atlantic variability
Interannual variability of the tropical Atlantic independent of and associated with ENSO: Part I. The North Tropical Atlantic

The interannual variability of the tropical Atlantic ocean-atmosphere system is examined using 50 years of sea-surface temperature (SST) and re-analysis data, and satellite data when available. A singular value decomposition analysis of 12- to 72-month bandpass filtered SST and zonal wind stress reveals two dominant modes of interannual variability. The SST anomalies are confined to the North Tropical Atlantic (NTA) in the first mode and extend over the equatorial and South Tropical Atlantic in the second mode. No evidence is found for an Atlantic SST dipole. The structure of the first (NTA) mode is examined in detail here, while the second mode has been described in a companion paper. In particular, the relationship of the NTA mode with El Nino-Southern Oscillation (ENSO) is investigated. There are 12 NTA events (seven warm and five cold) that are associated with ENSO, and 18 NTA events (seven warm and 11 cold) that are independent of ENSO. The ENSO-associated NTA events appear to be a passive response to remote ENSO forcing, mainly via a Pacific-North America (PNA)-like wave train that induces SST anomalies over the NTA through changes in the surface wind and latent heat flux. The NTA anomalies peak four months after ENSO. There does not appear to be an atmospheric response to the NTA SST anomalies as convection over the Atlantic is suppressed by the anomalous Walker circulation due to ENSO. The ENSO-independent NTA events also appear to be induced by an extratropical wave train from the Pacific sector (but one that is independent of Pacific SST), and forcing by the North Atlantic Oscillation (NAO) also contributes. As the event matures, the atmosphere does respond to the NTA SST anomalies, with enhanced convection over the Caribbean and a wave train that propagates northeastward to Europe
A study of precipitation variability in the Duero Basin (Iberian Peninsula)

Spatial and temporal average behaviour of winter precipitation in the Duero basin (DB) were analysed for 1958–1993.
Monthly observed data (observed data) from 34 weather stations and a subset of daily precipitation data from the
NCEP/NCAR reanalysis project (reanalysis data) were used.
The spatial variability of winter precipitation was examined using principal component analysis (PCA) for both types
of data. The winter precipitation fields are well represented by the first three principal components (PC), which describe
81% and 87% of the total variance for the observed and reanalysis data, respectively. The relationship between the three
leading PCs and circulation patterns was also investigated. The PC1 is related to the North Atlantic Pattern (NAO), East
Atlantic Pattern (EA) and Pacific North American Pattern (PNA). The PC2 is related to the East Atlantic/West Russia
Pattern (EAWR), while the PC3 depends mainly on Scandinavia Pattern (SCAND) influences.
The reanalysis data were used to calculate a 10-day period to study the intra-annual variation (S-mode of PCA) and
the spatial distribution of those precipitation amounts during the year (T-mode of PCA). For the intra-annual variation of
precipitation, two modes statistically significant were obtained. The first mode was characterized by a broad maximum
that extended from mid October to early April, and a minimum that extended from early May to September. The second
mode exhibited two maxima and a minimum. The first maximum occurred in late February and the second maximum
extended from early April to June. The minimum extended from mid July to early February. For the spatial distribution
of precipitation, we obtained three patterns. The ‘winter’ pattern, which showed a maximum over the western area, the
‘spring’ pattern with a maximum over the eastern area, and the ‘autumn’ with a maximum over the easternmost edge of
the basin
Half-century seasonal relationships between the Southern Annular Mode and Antarctic temperatures

In this short communication we examine the relationship between the Southern Hemisphere Annular Mode (SAM) and Antarctic near-surface temperatures using data from Antarctic stations for 1957-2004. This near half-century period is significantly longer than analysed in previous studies. Furthermore, the four seasons are considered independently while the longer datasets allow the temporal stability of the relationship to be investigated.\ud
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A general pattern of positive (negative) correlations between the strength of the SAM and temperatures in the northern Antarctic Peninsula (East Antarctica) is shown to be valid for the last half century but detailed differences are established between the seasons. These include a seasonal change in the sign of the relationship at one station, while at others there are single seasons when temperatures there are or, in some cases, are not significantly related to the SAM. Generally, SAM-temperature correlations are stronger across Antarctica in austral autumn and summer. Estimates of the contribution that trends in the SAM have made to Antarctic near-surface temperature change between 1957 and 2004 are greatest in autumn: in this season they exceed 1°C at half the 14 stations examined with a maximum change of –1.4°C. \ud
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There does not appear to have been any significant long-term change in the strength of SAM-temperature relationships over the period examined, even with the onset of ozone depletion. However, on an annual basis, the long-term relationship between the SAM and near-surface temperatures can be disrupted and even reversed at some stations although coastal East Antarctica appears stable in this respect. These findings give support to the exploitation of appropriate ice core data to determine longer-term changes in the SAM based upon transfer-functions derived from recent data. \u
Comparison of different procedures to map reference evapotranspiration using geographical information systems and regression-based techniques

16 páginas, 6 figuras, 8 tablas.This paper compares different procedures for mapping reference evapotranspiration (ETo) by means of regression-based techniques and geographical information systems (GIS). ETo is calculated following the method of Hargreaves (HG) from a dense database of meteorological stations in the northernmost semi-arid region of Europe, the Ebro valley. The HG method requires the calculation of estimates of extraterrestrial radiation (Ra). We calculated this parameter using two approaches: (1) the common approach that assumes a planar surface and determines the parameter as a function of latitude and (2) using a digital terrain model (DTM) and GIS modelling. The maps were made on a monthly basis using both approaches. We also compared possible propagations of errors in the map calculations for maps derived from modelled layers of maximum and minimum temperatures with those modelled using previously determined local ETo calculations. We demonstrate that calculations of Ra from a DTM and GIS modelling provide a more realistic spatial distribution of ETo than those derived by only considering latitude. It is also preferable to model in advance the variables involved in the calculation of ETo (temperature and Ra) and to subsequently calculate ETo by means of layer algebra in the GIS rather than directly model the local ETo calculations. The obtained maps are useful for the purposes of agriculture and ecological and water resources management in the study area.This work has been supported by the project CGL2005-\ud
04508/BOS financed by the Spanish Comission of Science\ud
and Technology (CICYT) and FEDER, PIP176/2005\ud
financed by the Aragón Government, and ‘Programa\ud
de grupos de investigación consolidados’ (BOA 48 of\ud
20-04-2005), also financed by the Aragón Government.\ud
Research of the third author was supported by postdoctoral\ud
fellowship by the Ministerio de Educación, Cultura\ud
y Deporte (Spain).Peer reviewe
Basin-wide warming of the Indian Ocean during El Nino and Indian Ocean dipole years

Basin-wide wintertime surface warming is observed in the Indian Ocean during El NiÃ±o years. The basin-wide warming is found to be stronger when El NiÃ±o and Indian Ocean Dipole (IOD) co-occur. The mechanisms responsible for the basin-wide warming are different for the years with El NiÃ±o only (El NiÃ±o without IOD) and for the co-occurrence (both El NiÃ±o and IOD) years. Strong westward propagation of downwelling Rossby waves is observed in the southern Indian Ocean during the IOD years. Such strong propagation is not seen in the case of the El NiÃ±o-only years. This indicates that the ocean dynamics play an important role in winter warming of the western Indian Ocean during the IOD years. The weak easterly wind anomalies in the El NiÃ±o-only years show no measurable impact on the Wyrtki Jets, but weakening or reversal of these jets is seen in the IOD years. This strongly suggests that the variability related to surface circulation is due to the local IOD forcing rather than El NiÃ±o induced wind anomaly. For the El NiÃ±o-only composites, surface heat fluxes (mainly latent heat flux and short wave radiation) play an important role in maintaining the basin-wide surface warming in the Indian Ocean. In the IOD-only composites (when there is no El NiÃ±o in the Pacific), such basin-wide warming is not seen because of the absence of ENSO (El NiÃ±o and Southern Oscillation) induced subsidence over the eastern Indian Ocean. For the years in which both El NiÃ±o in the Pacific and dipole in the Indian Ocean co-occur, warming in the western Indian Ocean is due to the ocean dynamics and that in the eastern Indian Ocean is due to the anomalous latent heat flux and solar radiation
Cloud-radiative impacts on the tropical Indian Ocean associated with the evolution of 'monsoon breaks'

A detailed diagnostic analysis of a suite of observed datasets was carried out with a view to understand the importance of cloud-radiative effects on the evolution of prolonged 'monsoon breaks' over the Indian region. The study particularly focuses on the role of clouds in affecting the sub-seasonal/intra-seasonal variability of sea surface temperature (SST) and atmospheric convection in the equatorial and south-eastern tropical Indian Ocean (SETIO) during monsoon-break transitions. A characteristic feature of the monsoon-break evolution is the appearance of suppressed convection over the SETIO region nearly 7-10 days prior to the commencement of a break spell over India. It is seen from the present analysis that the lack of cloud cover over the SETIO during the 'pre-break' phase leads to significant warming of the tropical Indian Ocean due to strong solar insolation at the surface. During the 'pre-break' phase, the net cloud-radiative forcing (NETCRF) at the surface is found to be typically around -30 Wm-2 and the mean SST in the SETIO is about 29.3Â°C. Following the transition to a monsoon-break phase, the cloud amount increases by about 25 over the SETIO region in association with intensified convection. The NETCRF at the surface over the SETIO averaged during the 'break' phase is found to be about -60 Wm-2 (i.e. a change of about -30 Wm-2 from the 'pre-break' phase). Consistent with the above change in the NETCRF, the SST in the SETIO shows a cooling of about 0.7Â°C, although the mean SSTs during the 'break' phase remain as high as 28.6Â°C. On the basis of the findings from this study, it is suggested that the SST warming during the 'pre-break' phase plays a key role in maintaining high SST and allows sustained convection to occur over the SETTO during prolonged monsoon breaks
Trends in ship wind speeds adjusted for observation method and height

Globally averaged wind speeds from archived ship reports show an increasing trend since the 1940s, which previous studies attributed to the gradual shift from visually estimated to anemometer-measured winds, and an increase in mean anemometer height. To test this hypothesis, adjustments to account for these changes were applied to individual ship wind observations in the International Comprehensive Ocean–Atmosphere Data Set (ICOADS). Annual means calculated from adjusted reports were compared to reanalysis near-surface winds in consistently well-sampled regions for the period 1958–2002. The adjustments to individual ship wind reports for known biases improve the homogeneity over the entire period and remove trends, prior to the early 1980s. However, for the 21-year period 1982–2002, trends remain in the annual mean spatially averaged adjusted winds, of 0.4 ms-1 decade-1 (6% decade-1) for estimated speeds, and of 0.2 ms-1 decade-1 (3% decade-1) for measured speeds. In contrast, co-located reanalysis near-surface wind speeds show little change, 1% decade-1 or less. Anemometers were installed on increasing numbers of ships during the period of study, even as many of these ships continued to report estimated winds. Part of the trend in estimated wind speeds is probably spurious, most likely a result of observers being increasingly influenced by readings from anemometers located well above 10-m. This influence is indicated by the gradual reduction in the tendency to underestimate nighttime marine winds. Results confirm earlier findings that reanalysis near-surface winds were biased low. The paper summarizes methods that could be employed to account for remaining inhomogeneities and thereby improve the quality of the marine wind climate record
The El Nino-Southern Oscillation and winter precipitation extremes over India

Daily rainfall data for the winter season October-December for the long period of 102 years 1901-2002 over southeast peninsular India have been used to study the characteristics of daily precipitation extremes. The frequency and intensity of extreme precipitation events do not show statistically significant long-term trend. The relationship of El Nino-southern oscillation index with these extremes shows that this index can be used to predict frequency and intensity of extreme precipitation events, 4-6 months in advance. However spell lengths of continuous wet/dry days are not modulated by variations in Pacific sea surface temperatures
Iberia in 1816, the year without a summer

The year 1816 was characterized by unusual weather conditions, in particular, by a cold and wet Summer season ('year without a summer') on both the European and North American continents. The eruption of Tambora, an active stratavolcano, on the Island of Sumbaya (Indonesia) in April 1815 has been identified as the main driving force for the strong 1816 temperature anomaly. This climate anomaly has been relatively well studied in central Europe, France, Scandinavia and the United Kingdom. The unusual unsettled weather and climate at mid-latitudes in 1816 and 1817 had major socioeconomic impacts. particularly in terms of a poor yield of agricultural production, malnutrition and consequentially an increased potential for diseases anti epidemics. The Iberian Peninsula was also affected by the intense climate anomalies during, those years. Documentary Sources describe the impact that the cold and wet summer of 1816 had on agriculture, namely the bad quality of fruits, delayed ripening of vineyards and cereals. It is within this context that we stress the relevance of recently recovered meteorological observed data, from 1816 onwards. for stations located in Portugal (Lisbon) and also for a longer period for the Spanish stations of Madrid, Barcelona and San Fernado-Cadiz. We have compared observed (station-based) and large-scale reconstructed seasonal temperature anomalies computed for the winter and summer seasons after the eruption (1816-1818). There is qualitative agreement between the two independent data sets, though some stations partly indicate stronger departures from the long-term averages for single years compared to neighbouring grid points. In particular. all available stations reveal a cold summer of 1816, mainly in July and August. In comparison to the 1871-1900 reference period, those two months were 2-3 degrees C cooler, close to what has been reported for central Europe. We also discuss the regional climate anomalies for those years (1816-1818) using independently reconstructed atmospheric circulation fields
An assessment of relationships between the Australian subtropical ridge, rainfall variability, and high-latitude circulation patterns

The monthly anomaly of the latitude of the subtropical ridge over eastern Australia (L) is a major regulator of synoptic-scale influences on Australia’s climate. Three datasets have been used to calculate L: observed Australia coastal mean sea level pressure (MSLP), Hadley and NCEP Reanalysis datasets. The choice of datasets used in this study appears to strongly influence results. Changes in the Southern Hemisphere Hadley cell and meridional circulation changes are associated with changes in L and it is shown that (1) L has statistically and physically significant relationships with seasonal rainfall in Australia; (2) the Antarctic Oscillation Index (AOI) has statistically significant relationships with Australian seasonal rainfall; and (3) L and Southern Annular Mode (SAM) are significantly related. Longer-term latitudinal shifts in L are also discussed