transport from south to north ropopause gap must be rather “not exceeding a week. rpretation of the observed proa is possible if a sudden tem> of vertical mixing or convection for instance, there is a sudden K profile from type A to type B 2 supply of fresh Rn™ from the the stratosphere is interrupted. low turbulence rate in this layer, j Rn™ in the lower stratosphere until it decays. A fraction of the ie tropopause will diffuse down- troposphere or upward into the here. Since the mixing rate is tropopause than in the lower he Rn™ content decreases more ; tropopause than in the layer | 2 WN, WO. : \ 5} r ™ se c 8 5 3 : o ; & . the Po™®*/Rn™ ratio. of the disturbed layer depends on e within the boundary layer. For = E i 2 os 7 \ \ i ! & — | Alaska series (May 1961) 2 | one } Hawaian Series (June 1961) r [ Calculated: =--- with K protile A dprowe nth a" “ (| Tropopause} pg 2 4 st 4 2} Profiles 4 7 ar B ‘ ‘ ‘ " \ a 0 e SN 5 107° O° | \ ct Rn-Profiles from MACHTA a. LUCAS (1962): : \ . a) i \ \ 3 10 = 4 \ 2 ¥ 2 4 Vy > c 5 5 -A___- co ~ € 10otoa ~ \ \‘ 3 | ' 5 ‘g at D ~_ = 6 86 0 2 4 Altitude (km) 6 8 20 | a 7 2b ye tt “o2z46801246 Altitude (km) Fig. 5. Comparison of observed Rnprofiles in the upper troposphere and lower stratosphere over Hawaii and Alaska with theoretical profiles (A, B) calculated with the A profiles on the rig 2 /Rn™ ratios are nearly equal but | ‘ © ia B10) time scale for the processes in- - decreases with increasing height level. At a given height the Pb™/ SY ¥ ‘atosphere. The main reason for rather short half-life of 3.8 days, sted for steady-state conditions. 4 —° yossible contaminations of the air gure. Tote i Rn “ Calculated with K-profile: QB wk leet 2 Specific activity (dps/cm?) ?n'* decay products. For the de0" (ty = 3.05 min), Pb™ (ti nd Bi™(tj. = 19.7 min), the theexpected, radioactive equilibrium pt in surface air. In the boundary oactive equilibrium is disturbed deposition of decay products at face which results in a downward vithin the boundary layer. yws the vertical profiles of Po™, * (Po™) in the boundary layer, Iculated with the aid of the K n Figure 1. In all cases a lack of y products with respect to Rn™ Tas A SA NB tt “ 7 OSTate 210 ntration with altitude above the cate the value of Rn™ as a tracer yf the exchange between tropo- see UN 7 10° 7 ~~ 2 _ result is a temporary, slow in- rther measurements are necessary ese preliminary results. In any 3807 INTERNATIONAL SYMPOSIUM ON TRACE GASES AND RADIOACTIVITY et cotsseeee [WN Po mencernen eee QA ——~— WNN —-— SSN aeesenenendernnenenesncttttien — eo weer Oa wee 42 aeprn ne reeetnaseeEte POeee pees” TFT ayeent” ae ae , = mee 410° wee aoe 2hae= = ee —— Rn cee ro 218 -5 10 ee Le _-_= — aan — ——— a * £ u _ eb an rtta Rn~. Bi 31 pin 1 yr nl = = Fig. 6. na § ~ ~~t-- ee = p78 “ss See, ~~. Po—— eee eee== ON ppo!4 Pee er ticm 75 NNN 10cm poul8 ppc! 5 piel4 == SSSSSS st im Altitude 10m see ee ee ee 100m Calculated vertical profiles of radon and its short-lived decay products in the boundary layer near ground level (£xo = 1 Rn atom/em’sec). 10