FFT and complex algebra-based methods of spherical harmonic analysis and synthesis are presented. Two computer programs in FORTRAN are developed based on the methods. Both general and special cases are discussed. Special cases involve the analyses of gravity changes of the hydrological origin and the atmospheric origin. Functionals of the Earth’s gravity field such as gravity anomaly and geoida...

A nonlinear generalisation of Principal Component Analysis (PCA) is applied to the 500mb geopotential height field of the Northern Hemisphere extratropical atmosphere. It is found that the low-frequency variability of the mid-troposphere is characterised by three distinct quasistationary states. The states are described and compared to those obtained from applications of cluster analyses and li...

Low-frequency variability in geopotential height records of the Northern Hemisphere is a topic of significance in atmospheric science, having profound implications for climate modeling and prediction. A debate has existed in the atmospheric science literature as to whether or not “regimes” or clusters exist in geopotential heights, and if so, how many such clusters. This paper tells the “detect...

The recovery of a high resolution geopotential from satellite gradiometer observations motivates the examination of high performance computational techniques. The primary subject matter addresses specifically the use of satellite gradiometer and GPS observations to form and invert the normal matrix associated with a large degree and order geopotential solution. Memory resident and out-of-core p...

Neural network models are used to reveal the nonlinear winter atmospheric teleconnection patterns associated with the El Niño-Southern Oscillation (ENSO) and with the Arctic Oscillation (AO) over the N. Hemisphere. The nonlinear teleconnections (for surface air temperature, precipitation, sea level pressure and 500 hPa geopotential height) are found to relate quadratically to the ENSO and AO in...

An inverse annual variation is observed between surface pressure on the highest mountain, which has an elevation of approximately 4000 m, and in the lowlands of Taiwan (a subtropical island in east Asia). This inverse annual variation in surface pressure of high and low elevation in low latitudes reflects, essentially, a vertical phase reversal of the tropical circulation, which is illustrated ...

The addition of an accurate pressure sensor to the inverted echo sounder (IES) has allowed for the development of a new method for calibrating the IES’s acoustic travel-time record without the need for coincident conductivity– temperature–depth (CTD) or expendable bathythermograph profiles. Using this method, the round-trip traveltime measurement of the IES can be calibrated into various dynami...