1845–2016 gridded dataset of monthly precipitation over the upper Adda river basin: a comparison with runoff series

Abstract

Abstract.A new high-resolution gridded dataset of 1845-2016 monthly precipitation series for the upper Adda river basin was computed starting from a network of high-quality and homogenised station records covering Adda basin and neighbouring areas and spanning more than two centuries. The long-term signal was reconstructed by a procedure based on the anomaly method and consisting in the superimposition of two fields which were computed independently: 1961-1990 monthly climatologies and gridded anomalies. Model accuracy was evaluated by means of station series reconstruction in leave-one-out approach and monthly relative mean absolute errors were found to range between 14 % in summer and 24 % in winter. Except for the period before the 1870s when station coverage is rather low, reconstruction errors are quite stable. The 1845-2016 monthly areal precipitation series integrated over Adda basin was finally computed. The robustness of this series was evaluated and it was investigated for long-term trend. While no significant trend emerged for precipitation, the analysis performed on 1845-2016 annual runoff values recorded at Lake Como outlet highlighted a negative trend. Runoff decrease is supposed to be mostly due to an increasing role of evapotranspiration linked to temperature increase, which is only partially compensated by the increase in glacier melting rate. In order to test the applicability of the gridded database for the reconstruction of extreme past events, the episode with the highest precipitation in Adda basin series (November 2002) was considered and the corresponding gridded fields of monthly anomalies and precipitation values were evaluated both with actual station density and with station densities corresponding to 1922 and 1882. Even considering 1882 station density, the main spatial patterns are well depicted proving the suitability of anomaly method to deal also with sparse station networks.

Drought Variability and Trend Over the Lombardy Plain from Meteorological Station Records

“…The series were retrieved from the regional services (ARPA Lombardia, ARPA Emilia-Romagna, ARPA Veneto, ARPA Piemonte), the archives of the former Italian Hydrographic Service and previous projects focusing on historical data collection and homogenization. Temperature series were checked for quality and homogeneity by means of the Craddock test (Craddock, 1968) and homogenization was applied on 8 maximum and minimum temperature series, while precipitation records were not checked since they were derived from the database already analyzed by Crespi et al (2018a) for assessing the hydrological cycle over the upper Adda basin. The 1951-2017 monthly precipitation and mean temperature, as average of maximum and minimum values, records were interpolated onto a 30-arc second resolution Digital Elevation Model (DEM) covering the domain by means of the anomaly method (see, e.g., New et al, 2000;Isotta et al, 2014;Scapin et al, 2015).…”

The impact of heat waves on food industry productivity: Firm‐level evidence from Italy

“…Climatologies are strictly linked to orography and require dense data coverage. Anomalies exhibit higher spatial coherence and can be computed starting from a less dense database while providing long and homogeneous time series properly covering the entire study period (see Brunetti et al, 2009;Crespi et al, 2018 for the methodology). High-resolution climatologies are based on the work of Brunetti et al (2014), where long-term temperature averages for 1961-1990 are computed starting from a dense network of weather stations.…”

Hydroclimatic Variability and Land Cover Transformations in the Central Italian Alps

“…Moreover, for the Adda river, long series of daily water levels were recorded at different hydrometric stations: Malpensata-Malgrate and Fortilizio (at Lake Como's outlet in Lecco). These data were combined with water stage-discharge relationships that are attested in scholarship [18][19][20] in order to carefully cross-check the data and construct a streamflow time series for the preregulation period from 1845 onwards [13,14]. After 1964, streamflow uptakes from the Spöl watershed, an Alpine tributary of the Inn river, were conducted to increase the Adda streamflow.…”

“…In the Adda river watershed, the mean areal annual precipitation depths were assessed in [13,16] starting from monthly point precipitations recorded by a rain gauge network, including a maximum of more than 250 stations located inside and in the outer region surrounding the watershed divide. The number of available stations progressively increased from the first decades of the 19th century, when about fewer than 10 stations could be used, up to 53 stations in 1860 and 250 in 1900.…”

“…In researching this paper, extended and high-quality time series of streamflow for five main rivers were collected: the rivers Adige, Mincio, Chiese, Oglio, and Adda, originating from the southern side of the Central Alps, from east to west. In particular, the time series of the Adda river [13,14] and the Adige river [15] span a period that is longer than a century and thus provide a nonordinary set of data that are highly valuable. The nonstationarity in precipitations and hydrologic losses can be deemed to be potential drivers of changes in runoff volumes on an annual time scale.…”