Like many other economic time series, US aggregate retail sales have strong trend and seasonal patterns. How to best model and forecast these patterns has been a long-standing issue in time-series analysis. This article compares arti"cial neural networks and traditional methods including Winters exponential smoothing, Box}Jenkins ARIMA model, and multivariate regression. The results indicate th...

One of the most important hydrological time series task is to determine if there is any trend in the data and how to achieve stationarity when there is nonstationarity behavior in data. Detecting trend and stationarity in hydrological time series may help us to understand the possible links between hydrological processes and global climate changes. In this study yearly, monthly and daily stream...

We present an analysis of seasonal cycle of the last 50 years of records of surface temperature in Italy. We consider two data sets which synthesize the surface temperature fields of Northern and Southern Italy. Such data sets consist of records of daily maximum and minimum temperature. We compute the best estimate of the seasonal cycle of the variables considered by adopting the cyclograms’ te...

The spatial and temporal variations of several environmental parameters over the Southeast Asia region recorded by remote sensing satellites for the past one to two decades are examined in relation to climate change. At the South China Sea, an increasing trend for sea surface temperature at a rate of 0.1 to 0.5 degree per decade was observed while the sea level anomaly increases at 2 to 6 cm pe...

A Global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on climatological-scale processes in high latitudes. The resulting trend estimates for the past period (1980–1999) agree well with observation5 based trend estimates. The results for the future period (2000–2019)...

The temporal distribution of monthly heating degree days (HDD) approximates a bell-shaped curve, usually with a January maximum. The first moment, or centroid, of this distribution can be taken as the midpoint of the heating season. Analysis of seasonal HDD centroids reveals significant inter-decadal trends in the Northern Plains. From 1950 to 1990, the timing of the HDD centroid is observed to...

Many seasonal adjustment procedures decompose time series into trend, seasonal, irregular and other components using simple non-seasonal nite moving-average trend lters. This report considers the design of such lters, both in the body and at the ends of series, based on speci ed criteria and simple dynamic models operating locally within the span of the lter. In the body of the series a exible ...

Integrated Water vapour (IWV) has been measured since 1994 by the TROWARA microwave radiometer in Bern, Switzerland. Homogenization techniques were used to identify and correct step changes in IWV related to instrument problems. IWV from radiosonde, GPS and sun photometer (SPM) was used in the homogenisation process as well as partial IWV columns between valley and mountain weather stations. Th...

Many seasonal adjustment procedures decompose time series into trend, seasonal, irregular and other components using simple non-seasonal nite moving-average trend lters. This report considers the design of such lters, both in the body and at the ends of series, based on speci ed criteria and simple dynamic models operating locally within the span of the lter. In the body of the series a exible ...