A BSTRACT. The ground-wave is the most importa nt mode of propaga ti on of r a dio waves in co nn ec tion with glaciology. In cold regions, sp ecia l conditions a re ofte n preva lent, invol v ing propaga tion ove r nonh o mogeneous earth , presen ce of stratified m edia, a nd low va lu es of conduc tivity and dielectric co nsta nt in the upper strata .A radio wave which propaga tes alo ng the Ea rth 's surface is, however, a lso inAuenced by atmos ph eri c re frac tion. As th e fre que ncy is increased , the roughness of the Earth 's surface must a lso be taken into acco un t. Thus seasona l va ri a tions a re to be expec ted due to ch a nges in the el ec trical a nd top ogra phi cal pro p erti es o f the ground as we ll a s the propagatio n conditions in the a tmosphere. Tt is, however, difficul t to sep a ra te these va rious effec ts, a fa ct which reduces the possibility of u sing ground-wave prop agation as a to ol for obta ining informa tio n on the p rop erties of the ground.Though the prop a gation of the ground-wave has been d ealt with both theore ti call y a nd experim e nta ll y fo r a lmost a century, some of the m os t valua ble informatio n of m ajor importance in cold regions h as b een o bta ined during th e last ten years. New th eoretica l pape rs on propaga tio n over s tra tified media o ffer a n explanation of the amplitude a nd phase va riations of the gro und-wave fi eld , whic h have been m easured , as w e ll as suggesting n ew m ethods to be tes ted a s possible a ids in sol ving gl aciologica l p ro bl ems.In man y prac ti cal cases of ground-wave propaga tion in a r cti c regions, the fo rmula for the ground-wave fi eld strength ca n b e written in a very simpl e way. Such a propaga tion mode l for frequencies a bove 30 MHz is presented in whic h a ccount is taken of the Earth's curvature, the terra in irregul a rities, a nd the effect o f th e tropospheric refrac tio n. This model al so includes the reco very efrect whic h occurs in propagation over mixed paths. A t th e higher frequen cies th e effec t of depol a riza tion becomes very important and sometimes ove rshadows fi eld-stre ngth varia tions du e to th e inAuence of th e el ec trica l prope rties. Fina lly some proble ms will be discussed whic h rema in to b e sol ved or have bee n gi ven ve ry little a tte nti o n up to now. R ESUME . Eifets des saisons sur la propagation des ondes au 5 01 dans les zones f roides. L es ondes terres tres sont le plus importan t m o d e d e propagation d es ondes radio en ra pport a vec la glac io logie. Da ns les r egions fro ides d es conditions speciales sont sou vent predominantes, p a rmi lesquelles un e propaga tio n sur une terre non homoge n e, la presence d e milie ux stratifi es et des b asses valeurs de la conduc ti vite et d e la con sta nte die lec trique dans la stra te superi eure.U ne onde ra dio qui se propage le long d e la surface te rres tre est a ussi, cep e nda n t, inAuen cee p a r la re fra ction atm os pherique. Si la freque n ce augmente il faut aussi prendre en c...
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