Ab stract
Th e re is no natu ral se ve n- day cycl e k now n, w h ich l asts ove r a l onge r pe riod of se ve ral ye ars. Re garding th e dynam ics in m e te orol ogy one can u nde rpin th is state m e nt w ith statistical te sts.
M any h u m an b e ings do “l ive ” a w e e k l y cycl e : w e e k days are u su al l y w ork ing days, w h il e w e e k e nds ove r- l ap w ith w ork fre e - days.
Se ve ral stu die s atte nd to th e w e e k l y cycl e s in air pol l u tion as for e . g.
oz one , PM 10 , and so on. O nl y a fe w are conce rne d w ith th e 7- day cycl e in cl im atol ogical variab l e s.
Th e au th ors of th is poste r re se arch in e xactl y th is topic and anal yse - in l ine w ith a m aste r th e sis - th e w e ath e r data from th e au tom atic stations ove r Sw itz e rl and.
Introduction
Bäu m e r e t al . fou nd w e e k l y pe riod- icitie s in cl im atol ogical variab l e s as ove r Ge rm any. By anal ysing data from 12 W M O stations b e tw e e n 19 9 1 u ntil 20 0 5 th e y fou nd a ne gative te m pe ratu re anom al y for w e e k e nds and a positive one for w e e k days. Th e anal ysis of th e pre cipitation data sh ow s th at th e re is ge ne ral l y m ore pre cipitation on w e e k e nds th an on w e e k days. Gong e t al . fou nd ve ry sim il ar re su l ts in Ch ina. Both grou ps assu m e th at th is se ve n- day- cycl e is cau se d b y ae rosol s, al th ou gh th e m e ch anism of action is not w e l l u n- de rstood.
Re sul ts for Sw itze rl and
Th e anal ysis of th e PM 10 data b e tw e e n 19 9 8 and 20 0 5 provide a significant w e e k l y cycl e w ith a m in- im u m at Su ndays (figure 1 ). Th e one side d W il coxon rank ing te st b e tw e e n th e m axim u m (W e dne s- day) and th e m inim u m (Su nday) is
W e e k l y pe riodicitie s in cl im atol ogy?
M onday Tu e sday W e dne sday Th u rsday Friday Satu rday Su nday
IAC
Institute for Atm osph e ric and Cl im ate Scie nce Sw iss Fe de ral Institute of Te ch nol ogy Z urich
Pe te r Barm e t Th om as K uste r M aste r Th e sis 20 0 8
h igh l y significant. Th is 7- day cycl e can al so b e se e n cl e arl y in th e pe ri- odogram w h ich sh ow s a pe ak at 1/7 and its m u l tipl e s (figure 2).
Th e pe riodogram of te m pe ratu re doe s not re ve al su ch a pe ak (fig- ure 3 ).
Th e anal ysis of th e te m pe ratu re an- om al y for e ach w e e k day provide s a 7- day- cycl e w ith a ve ry sm al l m ag- nitu de (figure 4 ). Th e W il coxon rank - ing te st b e tw e e n th e m axim u m and th e m inim u m doe s not sh ow a signi- ficance .
Random Sim ul ation
Th e random sim u l ation (50 0 0 ru ns of th e m ode l ) w ith th e re al te m pe r- atu re data provide s a h istogram w h ich re ve al s th at a m agnitu de of ab ou t 0 .2°C b e tw e e n th e m axim u m and th e m inim u m is th e m ost l ik e l y case (figure 5 ).
Lite rature
• D om iniq u e Bäu m e r and Be rnh ard Voge l (20 0 7), An u ne xpe cte d patte rn of distinct w e e k ly pe riodicitie s in clim atological variab le s in Ge rm any, Ge oph ysical Re se arch Lette r
• D ao-Yi Gong, D ong Gu o and Ch ang- H oi H o (20 0 6 ), W e e k e nd e ffe ct in di- u rnal te m pe ratu re range in Ch ina: O pposite signals b e tw e e n w inte r and su m m e r, Jou rnal of Ge oph ysical Re se arch - Atm osph e re s
• R D e ve lopm e nt Core Te am (20 0 5), R: A langu age and e nvironm e nt for statistical com pu ting
Su nday M onday Tu e sday W e dne sday Th u rsday Friday Satu rday
Errorb ars: ± 1 Standarde rror
Stations: Base l, Be rn, Ju ngfrau , Lu gano, Z u rich
Fig. 1: W e e k ly cycle of PM 10 ; valu e s from 19 9 8- 0 1- 0 1 to 20 0 5- 12- 31.
p- valu e < 2.2e - 16 , W ilcoxon rank su m te st w ith continu ity corre ction one side (M axim u m vs. M inim u m )
Anomaly [µg/m
3 ]
PM 10 : W e e k l y Cycl e
Fre q u e ncy
Fig. 2: Sm ooth e d Pe riodogram of PM 10 , value s from 19 9 8- 0 1- 0 1 to 20 0 5- 12- 31.
Black ve rtical line s sh ow th e fre q u e ncy of a w e e k (1/7 and m u ltiple s of it).
Spectrum
PM 10 : Pe riodogram
Fre q u e ncy
Fig. 3: Sm ooth e d Pe riodogram of Te m pe ratu re , valu e s from 19 9 8- 0 1- 0 1 to 20 0 5- 12- 31.
Black ve rtical line s sh ow th e fre q u e ncy of a w e e k (1/7 and m u ltiple s of it).
Te m pe rature : Pe riodogram
Spectrum
Anom aly (M axim u m - M inim u m ) [°C]
Fig. 5: Random sm u lation w ith th e re al te m pe ratu re data.
Te m pe rature : H istogram Sim ul ation
Frequency
Su nday Errorb ars: ± 1 Standarde rror
Stations: all au tom atic sw iss stations (total 113)
Fig. 4: W e e k ly cycle of Te m pe rature ; value s from 19 9 8- 0 1- 0 1 to 20 0 5- 12- 31.
p- valu e = 0 .0 9 5, W ilcoxon rank su m te st w ith continu ity corre ction one side (M axim u m vs. M inim u m )
M onday Tu e sday W e dne sday Th u rsday Friday Satu rday
Anomaly [µg/m
3 ]
