A millennial long March–July precipitation reconstruction for southern-central England

We present a millennial long dendroclimatic reconstruction of spring/summer precipitation for southern-central England. Previous research identified a significant moisture stress signal in ring-width data measured from oak trees growing in southern England. In this study, we build upon this earlier work, specifically targeting south-central England, to derive a well replicated oak ring-width composite chronology using both living and historical material. The data-set includes 352 living trees (AD 1629–2009) and 1540 individual historical series (AD 663–1925). The period expressed by at least 50 trees in any year is AD 980–2009. Calibration experiments identify the optimal seasonal predictand target as March–July precipitation (1901–2007: r² = 0.33). However, comparison with the long Kew Gardens precipitation record indicates a weakening in tree-growth/climate response from ~1800 to 1920 which we speculate may be related to smoke and sulphur dioxide (SO₂) emissions at that time which may have also contributed to a decrease in tree productivity. The time-series derived using the regional curve standardisation method to capture lower frequency information shows a mediaeval period with alternating multi-decade-long dry and wet periods, with AD 1153–1172 being the wettest reconstructed 20-year period in the whole record. Drier conditions are prevalent from ~1300 to the early sixteenth century followed by a period of increasing precipitation levels. The most recent four centuries of the record appear similar to the mediaeval period with multiple decade-long dry and wet periods. The late twentieth century is the second reconstructed wettest period. These centennial hydroclimatic trends are in broad agreement with independent regional scale hydroclimatic reconstructions from tree-ring (East Anglia), historical, speleothem and peat water level proxy archives in the United Kingdom and appear coupled with reconstructed sea surface temperature changes in the North Atlantic which in turn influence the Atlantic meridional overturning circulation and westerly airflow across the UK.     

The early instrumental warm-bias: a solution for long central European temperature series 1760–2007

Instrumental temperature recording in the Greater Alpine Region (GAR) began in the year 1760. Prior to the 1850–1870 period, after which screens of different types protected the instruments, thermometers were insufficiently sheltered from direct sunlight so were normally placed on north-facing walls or windows. It is likely that temperatures recorded in the summer half of the year were biased warm and those in the winter half biased cold, with the summer effect dominating. Because the changeover to screens often occurred at similar times, often coincident with the formation of National Meteorological Services (NMSs) in the GAR, it has been difficult to determine the scale of the problem, as all neighbour sites were likely to be similarly affected. This paper uses simultaneous measurements taken for eight recent years at the old and modern site at Kremsmünster, Austria to assess the issue. The temperature differences between the two locations (screened and unscreened) have caused a change in the diurnal cycle, which depends on the time of year. Starting from this specific empirical evidence from the only still existing and active early instrumental measuring site in the region, we developed three correction models for orientations NW through N to NE. Using the orientation angle of the buildings derived from metadata in the station histories of the other early instrumental sites in the region (sites across the GAR in the range from NE to NW) different adjustments to the diurnal cycle are developed for each location. The effect on the 32 sites across the GAR varies due to different formulae being used by NMSs to calculate monthly means from the two or more observations made at each site each day. These formulae also vary with time, so considerable amounts of additional metadata have had to be collected to apply the adjustments across the whole network. Overall, the results indicate that summer (April to September) average temperatures are cooled by about 0.4°C before 1850, with winters (October to March) staying much the same. The effects on monthly temperature averages are largest in June (a cooling from 0.21° to 0.93°C, depending on location) to a slight warming (up to 0.3°C) at some sites in February. In addition to revising the temperature evolution during the past centuries, the results have important implications for the calibration of proxy climatic data in the region (such as tree ring indices and documentary data such as grape harvest dates). A difference series across the 32 sites in the GAR indicates that summers since 1760 have warmed by about 1°C less than winters.     

Spring thermal resources for grapevine in Kőszeg (Hungary) deduced from a very long pictorial time series (1740–2009)

Since 1740 until now, the Book of Vine Branches encompasses beautiful pictorial representations of shoots and sprouts, collected every year on April 24th in the vineyards of the Hungarian town of K?szeg. A long time series (1740–2009) of sprouts phenological development coded with the BBCH scale is obtained through paintings visual inspection. Consequently, a model relating sprouts development with thermal resources accumulation is developed on the base of Wien daily air temperature series for the 1857–2009 period. Thermal resources is obtained with the Normal Heat Hours approach, a response curve method that takes into account the nonlinear response of phenological development to temperature. The model, calibrated and validated on the 1930–2009 period, shows an overestimation of thermal resources when applied to the 1857–1929, due to the more advanced phenology of that phase. Since this advance can be ascribed to genetics and management instead of more favorable thermal conditions, model outputs previous to 1930 are decreased by a constant factor. Finally, the 1740–2009 time series of grapevine spring thermal resources is obtained applying the model to the complete phenological time series. The analysis of the series highlights a first phase (1740–1780) characterized by high and stable availability of thermal resources during the 1740–1780, a second phase (1781–1820) with the lowest level of resources, a phase of intermediate availability (1821–1929) and a final present phase (1930–2009) with renewed high availability. The adopted method overcomes the lack of correlation for the post 1960 period shown by previous works.     

Effective wind stress over the great lakes derived from long‐term numerical model simulations

Numerical models were used to compute water circulations throughout the 1970 shipping season for Lake Erie and for the 1972 International Field Year on Lake Ontario. Simultaneous computations of surface elevations were compared with observed water levels to adjust the model results after the fact. As a by‐product of these simultations, effective stress coefficients over water can be estimated. The results support earlier evidence that the effective wind stress over water is larger than indicated by atmospheric boundary layer measurements.     

Information for Contributors

Acta Meteorologica Sinica (English edition) is an international academic journal in atmospheric sciences edited and published by Acta Meteorologica Sinica Press, sponsored by the Chinese Meteorological Society. It has been acting as a bridge of academic     

Information for Contributors

Acta Meteorologica Sinica (English edition)is an international academic journal in atmosphericsciences edited and published by Acta MeteorologicaSinica Press, sponsored by the Chinese MeteorologicalSociety. It has been acting as a bridge of academicexchange between Chinese and foreign meteorologistsand aiming at the introduction of the current advance-ments in atmospheric sciences in China. The journalcolumns include Articles. Note and Correspondence,and research letters. Contributions f…     

Information for Contributors

Acta Meteorologica Sinica(English edition)is an internationai academic journal in atmosphericsciences edited by the Chinese Meteorological Society.published and distributed by China MeteorologicalPress.It has been acting as a bridge of academic exchange between Chinese and foreign meteorologists andaiming at the introduction of the current advancements in atmospheric sciences in China.     

Information for Contributors

Acta Meteorologica Sinica (English edition) is an international academic journal in atmospheric sciences edited and published by Acta Meteorologica Sinica Press,sponsored by the Chinese Meteorological Society.It has been acting as a bridge of academic exchange between Chinese and foreign meteorologists     

Information for Contributors

Acta Meteorologica Sinica (English edition) is an international academic journal in atmospheric sciences edited and published by Acta Meteorologica Sinica Press, sponsored by the Chinese Meteorological Society. It has been acting as a bridge of academic exchange between Chinese and foreign meteorologists and aiming at the introduction of the current advancements in atmospheric sciences in China. The journal columns include Articles, Note and Correspondence, and research letters. Contributions from all over the world are welcome.     

Information for Contributors

Acta Meteorologica Sinica(English edition)is an international academic journal in atmosphericsciences edited by the Chinese Meteorological Society,published and distributed by China MeteorologicalPress.It has been acting as a bridge of academic exchange between Chinese and foreign meteorologists andaiming at the introduction of the current advancements in atmospheric sciences in China.     

Information for Authors

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Information for Contributors

Acta Meteorologica Sinica (English edition) is an international academic journal in atmospheric sciences edited and published by Acta Meteorologica Sinica Press,sponsored by the Chinese Meteorological Society.It has been acting as a bridge of academic     

Information for Authors

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Information for Contributors

Acta Meteorologica Sinica (English edition) is an international academic journal in atmospheric sciences edited and published by Acta Meteorologica Sinica Press, sponsored by the Chinese Meteorological Society. It has been acting as a bridge of academic exchange between Chinese and foreign meteorologists and aiming at the introduction of the current advance- ments in atmospheric sciences in China. The journal columns include Articles, Note and Correspondence, and research letters. Contri…