Long-term trends in planetary wave activity (2–15 days) at 80–100 km inferred from radio wave absorption

1994 ◽  
Vol 56 (8) ◽  
pp. 893-899 ◽  
Author(s):  
J. Laštovička ◽  
V. Fišer ◽  
D. Pancheva
Keyword(s):  
Radio Wave ◽  
Planetary Wave ◽  
Wave Activity ◽  
Wave Absorption ◽  
Radio Wave Absorption ◽  
Long Term Trends

scholarly journals Trends in the characteristics of the annual and semiannual variations observed in the radio wave absorption in the lower ionosphere

1999 ◽  
Vol 17 (10) ◽  
pp. 1336-1343 ◽  
Author(s):  
J. Laštovička ◽  
D. Pancheva
Keyword(s):  
Radio Wave ◽  
Lower Thermosphere ◽  
Lower Ionosphere ◽  
Positive Trend ◽  
Continuous Increase ◽  
Wave Absorption ◽  
Yearly Average ◽  
Radio Wave Absorption ◽  
Long Term Trends

Abstract. The continuous increase in concentration of greenhouse gases in the atmosphere is expected to cool higher levels of the atmosphere. There is some direct and indirect experimental evidence of long-term trends in temperature and other parameters in the mesosphere and lower thermosphere (MLT). Here we look for long-term trends in the annual and semiannual variations of the radio wave absorption in the lower ionosphere, which corresponds to the MLT region heights. Data from central and southeastern Europe are used. A consistent tendency to a positive trend in the amplitude of the semiannual wave appears to be observed. The reality of a similar tendency in the amplitude of the annual wave is questionable in the sense that the trend in the amplitude of the annual wave is probably induced by the trend in the yearly average values of absorption. The phases of both the annual and semiannual waves display a forward tendency, i.e. shift to an earlier time in the year. A tentative interpretation of these results in terms of changes of the seasonal variation of temperature and wind at MLT heights does not contradict the trends observed in those parameters.Key words. Ionosphere (ionosphere – atmosphere interactions; mid-latitude ionosphere) · Meteorology and atmospheric dynamics (middle atmosphere dynamics)

Interplanetary energetic ions and polar radio wave absorption

1989 ◽  
Vol 94 (A4) ◽  
pp. 3543 ◽  
Author(s):  
T. P. Armstrong ◽  
C. M. Laird ◽  
D. Venkatesan ◽  
S. Krishnaswamy ◽  
T. J. Rosenberg
Keyword(s):  
Radio Wave ◽  
Energetic Ions ◽  
Wave Absorption ◽  
Radio Wave Absorption
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