The daily average data derived from NCEP/NCAR reanalysis dataset and the interpolated outgoing long wave radiation(OLR) data provided by the National Oceanic and Atmospheric Administration(NOAA) are used and the cross wavelet and wavelet coherence transform methods are applied in this paper.

By combining the cross spectrum with the wavelet transform,the cross wavelet transform method is adopted to analysis on variations of regional climate.

Based on the sea ice grade, sea ice area and monthly atmospheric circulation index time series, wavelet and cross-wavelet methods are employed to investigate the long- term variation characteristics and climatic mechanism of sea ice in the Bohai Sea and the North Huanghai Sea.

Fur thermore the definition of wavelet cross-correlation function was,put forword,which can describe two fluctuation series under different scales and different laggings,by using cross-correlation function that can describe the whole correlation characters of two fluctuation series.

The paper introduces the fundamental principle of direction finding with amplitude comparison and analyses two ways of forming cross beam.

This thesis contain: some classical array configuration’s characteristics are listed and analyzed; the sparse spatial array’s synthesis method is studied under multiple restrictions; spatial power combination realized by cross beam method is studied; and the law of electric strength distribution in target area is investigated, too.