NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC I93 



In figure 68 we give the curves for the variations of the different 

 meteorological elements in Batavia. There are three kinds of curves : 

 a-curves w^hich show the variations in the directly observed monthly 

 means ; ^-curves in which these monthly means are s'moothed by tak- 

 ing twelve-monthly consecutive values ; and c-curves which are 

 smoothed by taking consecutive twenty-four-monthly means. 



By comparison of these different curves there is found a great 

 similarity even in many details. We shall consider particularly 

 the ^-curves. It appears that the greater variations are repeated 

 in all the curves, but so that the temperature variations occur some- 

 what later than the air pressure variations and the variations in 

 other elements. That the variations in air pressure occur often 

 several months before the variations in temperature is seen in many 

 instances in the a-curves, see for instance the years 1877 ^^'^ 1878, 

 where we find three well marked maxima in air pressure which 

 occur several months later in the temperature. 



It is natural to think that variations in air pressure call forth 

 variations in the cloudiness and thereby again variations in preci- 

 pitation and in the daily temperature amplitude. Variations in the 

 cloudiness will obviously call forth variations in the temperature 

 of the air. A great cloudiness at a station like Batavia in the 

 tropics is accompanied by low temperature. In our figures the 

 scale of cloudiness has been given with increasing values down- 

 wards, while for the temperature the scale increases upwards. 

 Changes in the temperature come in consequence of the earth's 

 capacity for heat somewhat later than the changes in the cloudiness. 

 But these are instantly accompanied by changes in the daily tem- 

 perature amplitude. The consequence of this is that the variations 

 in the daily temperature amplitude as a rule precede somewhat 

 the variations in the average temperature of the place, as is shown by 

 comparison of our curves in figure 68. We have drawn a &-curve 

 for the mean daily temperature amplitude. This shows on the whole 

 the same variations as the other curves. It may be of particular inter- 

 est to note that the well-marked minimum which we found in the 

 year 1904 for the surface temperature in the Atlantic Ocean is also 

 shown in all the curves of meteorological elements in Batavia except 

 in the curve for the wind velocity and for the daily temperature 

 amplitude. 



As the reader will see, the ^-curves and the c-curves follow one 

 another on the whole. Apart from some individual exceptions the 

 principal variations occur in both curves in common, which indi- 



