Modeling net ecosystem carbon dioxide exchange using temporal neural networks after wavelet denoising
Carbon dioxide ; Climatic change ; Comparative study ; Ecosystem ; Flow ; Forecast ; Model ; Neural network ; Peat bog ; Temperate zone ; Waveletanalysis
The potential of 6 temporal artificial neural networks (ANNs) augmented with and without 3 orthogonal wavelet functions was tested for predicting net ecosystem exchange of carbon dioxide (CO2) based on a long-term eddy covariance (EC) data set
for a temperate peatland. Multiple comparisons were made of (1) temporal ANNs with and without discrete wavelet transform (DWT) denoising; (2) denoising with the orthogonal wavelet families of Daubechies, Coiflet, and Symmlet; (3) different decomposition levels
Variation characteristics of temperature and precipitation in January and July and annual mean temperature and annual precipitation are analyzed with the help of cumulative anomalies, Mann-Kendall analysis and waveletanalysis. The research results
indicate that January precipitation presents an increasing trend after 1990, waveletanalysis result suggests that this increasing trend will continue in the near future. During 1900-1960, July precipitation is in a rising trend, but is in a declining trend
after 1960. Waveletanalysis shows that this declining trend will go on in the near future. Temperature variations in Shanghai are in fluctuations with 2 to 3 temperature rising periods.
Identifying hotspots of rip current activity using waveletanalysis at Pensacola Beach, Florida
; Waveletanalysis
these recently identified hotspots were present before Hurricane Ivan and if the development of the rip system is a response to the bar cycle. Waveletanalysis of aerial and satellite imagery from 1951 to 2004 was used to quantify the alongshore variation in bar
China ; Climatic trend ; Human impact ; Hydroclimatology ; Meltwater ; North-Western China ; Statistics ; Watershed ; Waveletanalysis
The hydro-climatic trends were examined for the lower reach of the Shiyang River Basin in NW China using the waveletanalysis and the Mann–Kendall (M–K) test. The results showed that the discharge significantly decreased during the last 5 decades
, while there was no noticeable change in precipitation. A 26-year periodicity in discharge was identified by applying the global wavelet spectra and continuous wavelet transform (CWT) method. Because the Shiyang River Basin is located in the cold region
The total precipitation of the highest 1 day, 3 day, 5 day, 7 day precipitation amount in the Yangtze River basin was analyzed with the help of linear trend analysis and continuous wavelet transform method. The aims of this paper are to demonstrate
basin respectively with the help of continuous wavelet transform method.
Based on hydrological data observed at Lijin gauging station from 1950 to 2008, the temporal changes of water discharge and sediment load of the Yellow River into the sea were analyzed by the waveletanalysis, and their impacts on the estuary were
Biodiversity ; Biogeography ; China ; Climatic data ; Ecological barrier ; Ecological corridor ; Model ; Monsoon ; Soil properties ; Southwest China ; Spatial analysis ; Spatial differentiation ; Vegetation ; Vegetation index ; Water vapor ; Wavelet
analysis
Primary Productivity (NPP) products of MOD13 and MOD17 as well as 1:1,000,000 vegetation type data were used. Based on ANUSPLIN spline function, GIS spatial analysis, waveletanalysis and landscape pattern analysis, regional differentiation characteristics
-Kendall test and continuous wavelet transform (CWT) methods. The CWT analysis revealed interannual to decadal modes of variability in precipitation. Similar but less sustained cycles are also found in streamflow. Correlation of precipitation with the El
This paper utilizes time-series analysis to examine precipitation and streamflow variability in northwestern Oklahoma over the period 1894-2003. Trends and periodicities in the hydroclimatic variables were investigated using, respectively, Mann
, the precipitation cycles are analyzed by waveletanalysis and the possible climate forcings, which drive the precipitation changes, are explored. The results show that : the precipitation in the middle and lower reaches of the Yellow River has inter-annual and inter
In this paper, the monthly precipitation and temperature data collected at 7 stations in the Ili River Basin from 1961 to 2007 were analyzed by means of simple regression analysis, running mean, db6 wavelet function and Mann-Kendall test. This study
Arctic Region ; Climate ; Climate oscillation ; Climatic trend ; Cold area ; Ice core ; Isotope analysis ; Oxygen 18 ; Spitsbergen ; Svalbard ; Temperature
the past 800 years and have been dated using a combination of known reference horizons and glacial modelling. The low frequency variability resolved by the waveletanalysis is similar to what has been found in various climate records including instrumental
cycles of 15–25 years and 35–50 years, which were detected by Morlet waveletanalysis, with the fluctuations being more frequent after 1870 than before.
Multiresolution image fusion by equalization of means and local variances : comparison with the fusion by the wavelet method
Belgium ; Europe ; Space remote sensing ; Spot ; Western Europe ; algorithms ; high resolution ; image analysis ; imagery ; melting ; statistical analysis ; theory ; urban areas ; variance analysis