Periodicity in time series of wind direction data

Summary The existence of periods of 24 and 92 hours has been proved on the basis of the analysis of time series of hourly mean wind direction data measured at the meteorological station in Praha-Ruzyn in the period from January to June, 1978. Besides, the closest mutual interdiurnal dependence of wind direction data observed at the climatological observation hour, at 7 a.m., has been proved. A method applicable to analysing time series of wind direction data by means of a computer is described.     

Analytical continuation of the gravity field for a two-dimensional body using an infinite series

Summary A procedure is derived which enables the analytical continuation of a two-dimensional gravity field to be expressed in the form of an infinite series. For this purpose, an apparatus is used which represents the two-dimensional analogy of Bicadze-type integrals.

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nuaa m¶rt;ua na aum aaumu n¶rt;u ¶rt;aumau n u¶rt; ¶rt;a. nm annaam n¶rt;mau ¶rt; aau uma muna ua¶rt;.

     

Analysis of uncertainties in regional climate model outputs over the Czech Republic

In this study we present results of uncertainty analysis in eight regional climate model (RCM) outputs over the area of the Czech Republic. The RCM simulations come from the EU 5th Framework program project PRUDENCE (Prediction of Regional scenarios and Uncertainties for Defining EuropeaN Climate change risks and Effects). Using the analysis of variance we have found that the main source of uncertainty in projected changes of mean seasonal air temperature is the driving global climate model. In case of precipitation changes, the RCM is the largest source of uncertainty in all seasons except for the spring. With the second method, the Reliability Averaging method, we have focused on the uncertainty coming from the RCM itself. The results of both methods showed that the relative contribution of the regional climate model to the uncertainty of simulated mean seasonal air temperature and precipitation changes is largest in summer and smallest in winter.     

Growth of accretionary wedges and pulsed ophiolitic mélange formation by successive subduction of trench‐parallel volcanic elevations

Fault‐bounded coherent belts alternating with belts of mélanges are common in accretionary wedges and are usually interpreted as a result of imbrication along subduction zone megathrusts. Using the Neoproterozoic/early Cambrian Blovice accretionary complex (BAC), Bohemian Massif, as a case example, we present a new model for the origin of alternating belts through the repetition of several cycles of (1) offscraping and deformation of trench‐fill sediments to form the coherent units, interrupted by (2) arrival and subduction of linear, trench‐parallel volcanic elevations. The latter process leads to an increase in the wedge taper, triggering mass‐wasting and formation of olistostromes. At the same time, ophiolitic mélanges form by disruption of an upper part of the volcanic ridge and incorporation of the disrupted ocean‐floor succession into the olistostromes. Specifically, the BAC represents a complete section across an accretionary wedge and records three such major pulses of ophiolitic mélange formation through subduction of an outboard back‐arc basin.