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<br />
<br />:1 TABLE 7
<br />SiM"ifiCt"'c~ I~wlz (%J for cha"g~z in laps~ rAUI for indiviJ"a/
<br />synopllC cJonu 0' Ua 1,,,(/ "nd 7()() mb. Only si,nifie'lrlu 11I",ls
<br />/u/ow 5% au SilO"'''. i meons significant increlUe uttd i mellns
<br /> Q significant decretUe
<br /> Sea-I.vol 100mb
<br /> S)'''''flIlocl... 0., Nillh' D., NiSIll
<br /> (.\l"ngmon,..DI
<br /> 0,....11 100 tll.O TO.a fo.o
<br /> A 10' To,o h.9
<br /> AN h6 To,o To,'
<br /> ANO
<br /> ^' 11.1
<br /> ^"
<br /> ^' 1a.0
<br /> A.w 101
<br /> AW T4.' tO,08
<br /> ANW TO,4 to.07
<br /> C '00 to.O
<br /> CN
<br /> eN' 12.0 Ta.!
<br /> "
<br /> m I..
<br /> "
<br /> "w
<br /> CW
<br /> CNW f"
<br /> N fl.6 TO,7 f"
<br /> NO
<br /> ,
<br /> "
<br /> ,
<br /> 'W 14.' 12.1 TLJ
<br /> W 11.7 To.o to_16
<br /> NW '00 To,o TO.D lo.ol
<br /> (b)Clv,OI
<br /> 0.....1 To.o 1u fo.o 13.8
<br /> A too il.' To.o U'-'
<br /> AN roo To.o
<br /> ^', foo to.2 t2.1
<br /> ^' fo<
<br /> ^', ro,
<br /> ^' to.4
<br /> ^,W TO.2 TO.3 "',
<br /> AW too to.O
<br /> ANW To.o to.O
<br /> C foo 10,0 To,o tOol
<br /> CN foo
<br /> eN, fn 11.7
<br /> " to..
<br /> m TO_2
<br /> " To_o TI.7 14.6
<br /> "W TH h.T
<br /> CW f..
<br /> CNW To,o To.o tu
<br /> N To,o TO.O
<br /> NO foo
<br /> , fo_o ro. ll.6
<br /> " to_o To.o
<br /> , fo,o f.,
<br /> 'w foo To.o
<br /> W fo.o to.o TO.l
<br /> NW 111.0 "" To.o
<br /> SY"Up"cc""",'''' mo<kup of.cur>.""" ICmI(OIIlIqclonic.<yclonic,ar
<br /> .".ighlland.d"..c"o"a"mn('.I..n<>nll<asl..IIOUlbJ.Fcrenmple:AE-
<br /> anticyclonic eas<erly. CSW . ~yclonic .".."lI_waw"ly. N - llnilht lIOI'1lInIy.
<br /> 142/ ARCTIC, ANTARCTIC, AND ALPINE! REsEARCH
<br />
<br />TABLE 8
<br />
<br />Be/Wun and within rynoplic type comJ1Dnenu 0/ duy/ime lapse
<br />rille chall8el7()Qmb)01llhe LrpfHrslope(CI vsDI). Theruord
<br />is divided inlo IWOpuiodso/eq"allengIJI (OCl J951-May J975)
<br />aNi (May J975-Dec 1997) and conlrasu beTween lapse TaUS in
<br />the early and tau ptriods uamined. Tht final col"mn gives lilt
<br />rOlio a/ ","IIin-type change 10 be/Wun-typt change
<br />
<br />SY""'P"c
<br />,,~ Ilelween-'ype Wilh,n_lype Ro,iojW!8)
<br />A 'W, -0,191 -Ug
<br />AN 0.021 -011.\6 -112
<br />AN' -0.1112 -O.IXI2 O,I~
<br />^' o~ -0001
<br />m ,~ ,'"" -0.'11
<br />^' -0.016 -0,003 11,16
<br />^,W -0.111'1 -0.031 1.9g
<br />AW o,~ -0.1l'J9 -l? ~~
<br />ANW 00l? -0.161 -6-O?
<br />C '00' -1),100 -19,H
<br />eN O.Olg -O,lll).t -11,21
<br />eN' ~O.ool -0.001 '"
<br />e' 000' -0.000 -0.11
<br />'" ''''' -0,001 -O.lJ
<br />" -O,OOS -0,0001 O.U
<br />e,w 0.1l~7 -O.Ol'1 -0,69
<br />~ 0.014 -0.04~ -],I~
<br />eNW 0.023 -O.04g -2.0~
<br />N 0.0]4 -O.1ll2 -1.91
<br />"' ''''' -0.001 -0.13
<br />, -I),OOS -1),00] '"
<br />" -000) -0,001 0.24
<br />, -1),019 -11023 1.22
<br />'W 0.058 -O,lllS -),26
<br />W O.l34 -0492 -1.47
<br />"" 0.313 -0.4Il -III
<br />
<br />tween lapse rales and W arc weak. However. IIsin&; me sea-level
<br />classification. an increase in W gives shallownocrumallapse
<br />rates. cloud-free downslope flow encouraging temperaf\lre in-
<br />version fannation. The relationship of lapse rate wim S changes
<br />sign dependingoD allUQspheric level. Using the sc:a-levelp-id.
<br />soutberlyllowsareanociated with shallow lapse rates, but this
<br />is reversed at hiih atmospheric levels (700 and 500 mb). F has
<br />IinleinlluenceonlapseratC5.
<br />Carrclalionsbetweell circulation indices and lapse rates on
<br />the uppc:r slope (CIIDI) are oonsiderably different (nolshown).
<br />Daytime lapse rates arc steeper for low S (northerly flows), rugh
<br />W (weslerly flows), hia:h F (strong circulation). and low Z (an-
<br />ticyclonic tendencies). At nightlhc relationship wim Z is re-
<br />vened_ Clear slUes associated wJlh low Z encourage rapid ra-
<br />dialion loss and subsequenl inversion formalion. Relationships
<br />with S. W. and F remain similar al nip!.
<br />Figure 7 shows mean lapse nile. for each synoplic class
<br />(850 mb) for both the overall LangmontIDl conll'a&! and the
<br />upper slope (CIIDI). Distinct conuasts arc shown. For Lo[lg-
<br />montIDl there arc daytime conuasts between nonherly and
<br />southerly airflows and anlicylonic and cyclonic condilions (Fig.
<br />7a). At night (Fia:_ 7b) strongest differentiation occllrs belween
<br />wC$terly and easterly airflows (Sleeper far easlerly flows). The
<br />contrast belween anLicyclonic and cyclonic classes is also en-
<br />banced. Pancms arc completely differelll for the IIpper slope rate
<br />(niS. 7c. 7d). Most noticeable is lhccbange in the siglloflhe
<br />east/wCSl cmllrllSt, westerly flows now producing steeper lapse
<br />rates dllling the day. During the Dlght. soulherly flows inslead
<br />
<br />
<br />"
<br />,
<br />
<br />.
<br />
<br />
<br />-". ''''$E.,.'NOC. C. '. c.. E < 0 "
<br />AN" AS.O C C..,,'c..,.."".. ,....
<br />
<br />::~III'1~mIllIIIDl' .
<br />
<br />.'
<br />
<br />.. N L L _"
<br />.., 'N''''''.'.>
<br />
<br />
<br />...,.. ..
<br />
<br />'c CN<'..es.'N.....'...
<br />
<br />FIGURE 7. Mean lapse n>res lor synoplic chusu 0/ 850 mb: (a' O~~rolllapse role (LDngtnOnlIDJ)
<br />daily maximum ItmptrClluu: (b) a,'eralllapse rolt (LongmontIDl) daily minimum lemptralUu: (c) Upper
<br />dope lopse rale (CIIDI) dOily moximum lemptrClluu: (d) Upper ~Iope lapse rCII~ (CII DJ) daily minimum
<br />umperaturt. Tht horizonlallme reprtstnls Iloe dry adiabal;c lapst rolt in ~ach cast. Nolt tltallh~ venl,al
<br />scale for groph c i. diff~rent.
<br />
<br />of westerly ones nOW show sn-Howesl rates. Thus lhc synoptic
<br />ClllSsification is compeleDl al differemialing lapse rale behaviar
<br />but relationships between circulation indIces, lhe classification
<br />and lapserales arc complex. 1ncre is a signiticant ntgative cor-
<br />rclatiOllbelwccn lhc IIpper and lower slope lapse rlIleSOn a daily
<br />basis.
<br />1nc synopllc approach will also be IIsed lO investigate
<br />whcther long-tenn changes inlOlpsc rates a.re a result of changing
<br />frequencies of atlUQsphenc circlllalion pallems {belween-type
<br />climate chutlle),or whelher lhcy occur within individual circu-
<br />lalion types (within-lype climate change). For each synoplic
<br />class a time-serics of daily lapse rales was examined. Many clllS-
<br />ses show significant lapse rate change over the 46-yr record.
<br />
<br />TABLE 9
<br />
<br />Sy~u,"",lk indu changlS wilhm airflow type.. In Iht final col-
<br />umn Ihe l<'Iter,nd"oles whtlhtrlhesigltljicafllchonguinmr-
<br />]low characttr /i~'ed art in Iht some dlrtCI;OIl "~Ihost uptcud
<br />10 accoufll/or tht change In tap.e ralt obstfvtJ (Y '" yn. N =
<br />/fO, ~ no/ txptcltd 10 have a large inJIuenct on lapu rDln)
<br />
<br /> Acc"","'
<br /> A"now ,.
<br />Lev.l "~ Si8ml\con,wilhin.IYf'<ind..chanll.' lap-",'!
<br />S.a~v.1 A _.W I...S ,
<br /> C ~..s ,
<br /> 'W -, ~, N
<br />'oo~ W 1e..S ,
<br /> C _d
<br /> ANW ....W _d I...f ,
<br /> NW I...W --, I...f N
<br /> 'W Ic..f
<br />
<br />Significant changes al 0.1% arc lisled mTable 7. Se'!-level and
<br />700-mh classificatians oDlY:lfe shown. as the 850-mb classifi-
<br />cation was unavailable before 1959, and 500-mb resulls were
<br />similar 10 700 mh. In most caseS lapsc:ra'es :lfegelUngSlrunger.
<br />Using me sea_levclclassification lhis isoccuning fur 7 synopuc
<br />types during the day and 12 at night (the whole slope). An ex-
<br />ception isnighuimc lapse rate weakening for cyclanic soulbeas-
<br />lerbes. Al 700 mb simil:lf SlfCngtherung is seen. but only fur 5
<br />classes dllling the day and 7 atlllght. On me upper slope (CII
<br />OJ). stronger lapse rales are..,becoming much mot!: common. All
<br />but 2 classes show significant daytime Slrengthening of lapse nile
<br />in lhe sca_levclclassification_anlydroppmg 10 17 classes al 700
<br />mb. Classes with weslerly (or nonhwesterly) cOmponenlS often
<br />showlhcmoslmarl<edchange,indicalingchangelObesynop-
<br />tically specific. Lapse rate changes on the IIpper slope are less
<br />ConsiSlenl al night.
<br />Variable frequencies of synoptic classes (especiallyal.700
<br />mb). could encourage lhe more popular classes {e,g. weslerlies)
<br />to show SlrOnger lemporallrends in lapse rale. This wOllld occur
<br />iflhey were to have a mOre cven dislribulion of days throughaul
<br />Ihe record periotl (B=y. pers. comm.. 1998). The less frequenl
<br />classes could fail 10 sample the whole lime perio<l. ThIs was
<br />examined by using Hests (Gossel!. 1908) to delcnnine whelher
<br />lhe me'!n date for each synoptic class was Slgnificanlly differenl
<br />from the mean dale of lhe whole rc<.::ord. This showed lhal un-
<br />even temporal sampling can be ruled out as a reason for lhe
<br />slronger lemporallrends for weslerly and northwesterly classes.
<br />Only the 700 mb ANE class suffered from temporal bias (aI5%).
<br />The metho<l of Barry and Perry (1973) was used 10 slalis-
<br />tically separate lhe wimin-Iype and between-type camponents of
<br />lapse rale change. Delails of the mcllwdology are also given in
<br />Barr}' et aI. (1981)_ TIle record was divided mlO IWO halves of
<br />
<br />N. f'EPIN/14)
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