1. The equatorial lower ionosphere like indicator of solar activity and tropical cyclone action Liudmila Vanina-Dart Space Research Institute, Moscow, Russia (vandart@seeingear.org) This paper presents the results of rocket-borne measurements of the electron density in the equatorial ionospheric D layer at the rocket testing ground Tumba ( India ). Special attention will be paid for ionosphere during tropical cyclones. For example, was detected that possible large-scale response of ionospheric state can be the “fast” depletion (2-4 times) in electron density at heights of 50 – 80 km during the action of the active phase of a tropical cyclone. The author analyzed data including the space weather influence fact to equatorial ionosphere.

2. Thus, the catastrophic atmospheric vortex systems play an important (and possibly determining) role in the formation of the temperature regime of the Earth (the greenhouse effect), removing excess heat and preventing from strong overheating of the atmosphere (of its tropical part) and the surface ocean layer in the tropical zone It is known that the whole spectrum of powerful dynamical phenomena is originated in the tropical zone of the atmosphere. The most intense of these phenomena are TCs, which are possible potential sources of the influence from “below”. Catastrophic atmospheric vortices, which originate near the equator, and develop in the tropical zone of the Earth’s atmosphere, present a peculiar mechanism of effective heat effluence under such atmospheric conditions, when the action of ordinary mechanisms (the main mechanisms are turbulent convection and global circulation) becomes evidently insufficient. Thus, the catastrophic atmospheric vortex systems play an important (and possibly determining) role in the formation of the temperature regime of the Earth (the greenhouse effect), removing excess heat and preventing from strong overheating of the atmosphere (of its tropical part) and the surface ocean layer in the tropical zone.

3. Gherzi (1946) was the first to suggest that ionospheric soundings could be used as an aid for weather forecasting and for predicting the movement of typhoons. But much of this work was based on misconceptions and some of his claims on this subject have not stood up to scrutiny. Observations have shown that the passage of tropical storms can lead to perturbations in the plasma drift [Bishop et al., 2006]

4. Relationships between meteorological and ionospheric phenomena come about through vertical motions in the ionosphere induced by underlying large scale weather systems or from gravity waves which originate from the surface or upper troposphere. The amplitude of gravity waves (Gws) of certain frequencies increases exponentially a with height because of the decreasing density. The growth factor is given, if by the square root of the ratio of the atmospheric density at source and at the height of interest. A displacement at the earth's surface of a few centimetres can originate an atmospheric GW which will grow in amplitude to several kilometres at ionospheric levels. Growth factors of 10 4 to 10 5 are typical. The layers of constant electron density move up and down with oscillatory motions similar to the acoustic pressure wave itself. Normal ocean waves do not generate acoustic waves which grow exponentially with height because their periods are well below the Brunt-Vaisala period of the atmosphere (about 300s) and their speeds are much less than the speed of sound (330 m/s); a combination which gives rise to atmospheric waves which quickly fade with height weakly ionised layers.

5. One of the first papers presented the special processing results of rocket-borne measurements of the electron density in the equatorial ionospheric D layer over the troposphere catastrophes ( tropical cyclones ) area at the rocket testing ground Tumba ( India ). Remote sensing observations for tropical cyclones were performed over the North Indian Ocean, the West North Pacific and the South Indian Ocean. It was detected that possible large-scale response of ionospheric state can be the “fast” depletion (2-4 times) in electron density at heights of 50 – 80 km during the action of the active phase of a tropical cyclone. It is the first observated finding of the “high-rate” action on ionosphere layer by troposphere intensive vortical systems. We suppose that the wide-spead influence of tropical cyclone is carried in the wide latitude zone. We proposed, that the lower ionosphere in the Tumba region (8 0 N, 77 0 E) has a more than only “local” influence of tropical cyclones in the North Indian Ocean the lower ionosphere of this region has global influence from the West North Pacific to the South Indian Ocean. ISSN 00167932, Geomagnetism and Aeronomy, 2008, Vol. 48, No. 2, pp. 245–250. © Pleiades Publishing, Ltd., 2008.

6. ISSN 00167932, Geomagnetism and Aeronomy, 2008, Vol. 48, No. 2, pp. 245–250. © Pleiades Publishing, Ltd., 2008. Table 1. Solar and geophysical information accompanying rocket flights in May–June 1985 Flight Flight Flight Zenith, deg F 10.7 Kp Ap Dst, N data time (UT) angle χ nT 46 01.05.1985 11.34 71 81 3 10 34 47 08.05.1985 11.55 76 84 3 8 5 48 16.05.1985 11.54 76 95 2 11 19 49 22.05.1985 11.35 71 83 1 5 3 50 29.05.1985 11.55 75 73 0 4 4 51 05.06.1985 11.37 70 84 1 5 1 52 19.06.1985 11.58 74 72 1 3 8 53 27.06.1985 12.16 77 70 2 13 13 Based on a synchronous analysis of the series of rocket measurements of the electron concentration and thermodynamic parameters of the lower ionosphere in the equatorial region and on the remote sensing data on tropical cyclogenesis in the northern Indian Ocean, we for the first time experimentally registered a decrease in [e] in the D region at the distance of about 1000 km (in the horizontal projection) from the nucleus of a tropical cyclone in the active phase. A decrease in electron concentration is maximal (on average, a factor of 3–4) at altitudes of 71 ―/+ 3 km. In this case the lower boundary of the D region ascends by a few kilometers (not more than 5 km). During the action of TC, the temperature also slightly increased (by about 3°) at the stratopause altitude.

7. Rtc([e],F) — the correlation coefficient between the electron concentration and the 10.7-cm Solar radio flux in days with TC, Rq([e],F) — the correlation coefficient between the electron concentration and the 10.7-cm Solar radio flux in days without TC.

8. MONTHLY MEAN SUNSPOT NUMBERS ======================================================================= Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ----------------------------------------------------------------------------------------------------------------------------- 1979 138.0 101.5 134.4 149.5 159.4 142.2 188.4 1980 159.6 155.0 126.2 164.1 179.9 157.3 136.3 135.4 1984 9.7 76.4 46.1 37.4 25.5 15.7 1985 16.5 15.9 27.5 24.2 30.7 11.1 3.9 1986 23.2 15.1 18.5 13.7 1.1 1987 39.6 33.0 27.1 1988 59.0 40.0 76.2 88.0 60.1 120.1 125.1 125.1 79.2 1989 161.3 165.1 ftp://ftp.ngdc.noaa.gov/STP/space-weather/solar-data/solar-indices/sunspot-numbers/international/tables

9. Height, км Rq([e],F),% (1985,1988 yy.) Rtc([e],F),% (1985,1988 yy.) Rq([e],F),% (1979- 1989 yy.) Rtc([e],F),% (1979- 1988 yy.) 60---- 65-44-- 70-64-39 7564664533 8065587054

10. D ate: 28 MAY-1 JUN 1985 Tropical Storm #2 ADV LAT LON TIME WIND PR STAT 1 15.10 67.40 05/28/06Z 30 - TROPICAL DEPRESSION 2 15.80 67.50 05/28/12Z 35 - TROPICAL STORM 3 16.50 67.60 05/28/18Z 40 - TROPICAL STORM 4 17.20 67.70 05/29/00Z 45 - TROPICAL STORM 5 17.90 67.80 05/29/06Z 45 - TROPICAL STORM 6 18.60 68.10 05/29/12Z 50 - TROPICAL STORM 7 19.30 68.30 05/29/18Z 50 - TROPICAL STORM 8 20.10 68.50 05/30/00Z 50 - TROPICAL STORM 9 20.80 68.40 05/30/06Z 45 - TROPICAL STORM 10 21.40 68.30 05/30/12Z 45 - TROPICAL STORM 11 22.10 68.30 05/30/18Z 40 - TROPICAL STORM 12 22.80 68.40 05/31/00Z 40 - TROPICAL STORM 13 23.30 68.50 05/31/06Z 35 - TROPICAL STORM 14 23.90 68.80 05/31/12Z 30 - TROPICAL DEPRESSION 15 24.40 69.00 05/31/18Z 25 - TROPICAL DEPRESSION 16 24.80 69.50 06/01/00Z 20 - TROPICAL DEPRESSION

11. 46 01.05.1985 47 08.05.1985 48 16.05.1985 49 22.05.1985 50 29.05.1985 51 05.06.1985 52 19.06.1985 53 27.06.1985 Tumba region (8 0 N, 77 0 E) Tiruchirapalli (TI311) 10.8 0 N 78.7 0 E

12. D ate: 22-25 MAY 1985 Tropical Storm #1 ADV LAT LON TIME WIND PR STAT 1 16.20 87.80 05/22/18Z 30 - TROPICAL DEPRESSION 2 16.60 88.10 05/23/00Z 30 - TROPICAL DEPRESSION 3 17.10 88.40 05/23/06Z 35 - TROPICAL STORM 4 17.70 88.80 05/23/12Z 40 - TROPICAL STORM 5 18.30 89.30 05/23/18Z 45 - TROPICAL STORM 6 19.00 89.70 05/24/00Z 45 - TROPICAL STORM 7 19.70 90.00 05/24/06Z 50 - TROPICAL STORM 8 20.50 90.40 05/24/12Z 55 - TROPICAL STORM 9 21.40 90.90 05/24/18Z 60 - TROPICAL STORM 10 22.50 91.20 05/25/00Z 60 - TROPICAL STORM 11 23.90 91.60 05/25/06Z 30 - TROPICAL DEPRESSION

15. Date: 25 OCT-2 NOV 1981 Tropical Storm #1 ADV LAT LON TIME WIND PR STAT 1 7.00 82.40 10/25/06Z 20 - TROPICAL DEPRESSION 2 7.70 81.50 10/25/12Z 25 - TROPICAL DEPRESSION 3 8.40 80.60 10/25/18Z 25 - TROPICAL DEPRESSION 4 9.00 79.90 10/26/00Z 25 - TROPICAL DEPRESSION 5 9.50 79.10 10/26/06Z 25 - TROPICAL DEPRESSION 6 9.90 78.40 10/26/12Z 30 - TROPICAL DEPRESSION 7 10.40 77.70 10/26/18Z 30 - TROPICAL DEPRESSION 8 10.80 76.80 10/27/00Z 35 - TROPICAL STORM 9 11.30 75.80 10/27/06Z 40 - TROPICAL STORM 10 11.70 74.80 10/27/12Z 45 - TROPICAL STORM 11 12.00 73.90 10/27/18Z 50 - TROPICAL STORM 12 12.10 73.10 10/28/00Z 55 - TROPICAL STORM 13 12.30 72.20 10/28/06Z 60 - TROPICAL STORM 14 12.40 71.40 10/28/12Z 60 - TROPICAL STORM 15 12.60 70.70 10/28/18Z 60 - TROPICAL STORM 16 12.70 70.10 10/29/00Z 60 - TROPICAL STORM 17 12.90 69.40 10/29/06Z 60 - TROPICAL STORM 18 13.00 68.70 10/29/12Z 50 - TROPICAL STORM 19 12.90 68.00 10/29/18Z 45 - TROPICAL STORM 20 12.80 67.10 10/30/00Z 40 - TROPICAL STORM 21 13.50 66.70 10/30/06Z 40 - TROPICAL STORM 22 14.20 66.80 10/30/12Z 45 - TROPICAL STORM 23 14.90 67.10 10/30/18Z 50 - TROPICAL STORM 24 15.50 67.30 10/31/00Z 55 - TROPICAL STORM 25 16.40 67.30 10/31/06Z 60 - TROPICAL STORM 26 17.30 67.20 10/31/12Z 60 - TROPICAL STORM 27 18.20 67.40 10/31/18Z 60 - TROPICAL STORM 28 19.10 67.80 11/01/00Z 60 - TROPICAL STORM 29 20.00 68.20 11/01/06Z 55 - TROPICAL STORM 30 20.80 68.60 11/01/12Z 50 - TROPICAL STORM 31 21.60 69.20 11/01/18Z 45 - TROPICAL STORM 32 22.40 69.90 11/02/00Z 35 - TROPICAL STORM Kodaikanal (KO310) 10.2 0 N 77.5 0 E

16. Date: 10-20 OCT 1980 Tropical Storm #1 ADV LAT LON TIME WIND PR STAT 1 8.80 92.30 10/10/06Z 25 - TROPICAL DEPRESSION 2 8.90 92.80 10/10/12Z 25 - TROPICAL DEPRESSION 3 9.10 93.20 10/10/18Z 25 - TROPICAL DEPRESSION 4 9.40 93.50 10/11/00Z 20 - TROPICAL DEPRESSION 5 9.60 93.30 10/11/06Z 20 - TROPICAL DEPRESSION 6 9.70 92.90 10/11/12Z 25 - TROPICAL DEPRESSION 7 9.70 92.50 10/11/18Z 25 - TROPICAL DEPRESSION 8 9.80 92.10 10/12/00Z 25 - TROPICAL DEPRESSION 9 10.10 91.80 10/12/06Z 25 - TROPICAL DEPRESSION 10 10.70 91.70 10/12/12Z 25 - TROPICAL DEPRESSION 11 11.00 92.00 10/12/18Z 25 - TROPICAL DEPRESSION 12 11.20 92.40 10/13/00Z 25 - TROPICAL DEPRESSION 13 11.30 93.00 10/13/06Z 25 - TROPICAL DEPRESSION 14 11.40 93.50 10/13/12Z 25 - TROPICAL DEPRESSION 15 11.10 93.90 10/13/18Z 25 - TROPICAL DEPRESSION 16 10.90 94.00 10/14/00Z 25 - TROPICAL DEPRESSION 17 10.60 93.90 10/14/06Z 25 - TROPICAL DEPRESSION 18 10.40 93.60 10/14/12Z 25 - TROPICAL DEPRESSION 19 10.10 92.70 10/14/18Z 25 - TROPICAL DEPRESSION 20 9.90 91.50 10/15/00Z 25 - TROPICAL DEPRESSION 21 9.80 90.20 10/15/06Z 25 - TROPICAL DEPRESSION 22 10.10 88.90 10/15/12Z 25 - TROPICAL DEPRESSION 23 9.70 87.60 10/15/18Z 25 - TROPICAL DEPRESSION 24 8.90 86.10 10/16/00Z 30 - TROPICAL DEPRESSION 25 8.70 84.90 10/16/06Z 30 - TROPICAL DEPRESSION 26 8.60 83.80 10/16/12Z 35 - TROPICAL STORM 27 8.50 82.90 10/16/18Z 35 - TROPICAL STORM 28 8.40 82.10 10/17/00Z 35 - TROPICAL STORM 29 8.30 81.30 10/17/06Z 30 - TROPICAL DEPRESSION 30 8.20 80.50 10/17/12Z 25 - TROPICAL DEPRESSION 31 8.00 79.30 10/17/18Z 25 - TROPICAL DEPRESSION 32 7.80 77.50 10/18/00Z 25 - TROPICAL DEPRESSION 33 7.60 76.20 10/18/06Z 25 - TROPICAL DEPRESSION 34 7.70 75.00 10/18/12Z 25 - TROPICAL DEPRESSION 35 7.80 74.10 10/18/18Z 25 - TROPICAL DEPRESSION 36 8.00 73.20 10/19/00Z 25 - TROPICAL DEPRESSION 37 8.30 72.20 10/19/06Z 25 - TROPICAL DEPRESSION 38 8.90 71.10 10/19/12Z 25 - TROPICAL DEPRESSION 39 9.60 70.00 10/19/18Z 25 - TROPICAL DEPRESSION 40 10.50 69.10 10/20/00Z 25 - TROPICAL DEPRESSION Kodaikanal (KO310) 10.2 0 N 77.5 0 E

17. Date: 12-19 NOV 1980 Tropical Storm #3 ADV LAT LON TIME WIND PR STAT 1 11.30 74.30 11/12/06Z 20 - TROPICAL DEP 2 11.40 73.70 11/12/12Z 25 - TROPICAL DEP 3 11.40 73.20 11/12/18Z 25 - TROPICAL DEP 4 11.50 72.70 11/13/00Z 25 - TROPICAL DEP 5 11.70 72.20 11/13/06Z 25 - TROPICAL DEP 6 11.90 71.70 11/13/12Z 25 - TROPICAL DEP 7 12.10 71.40 11/13/18Z 25 - TROPICAL DEP 8 12.30 71.20 11/14/00Z 25 - TROPICAL DEP 9 12.50 70.90 11/14/06Z 25 - TROPICAL DEP 10 12.80 70.60 11/14/12Z 25 - TROPICAL DEP 11 13.10 70.30 11/14/18Z 25 - TROPICAL DEP 12 13.40 70.00 11/15/00Z 30 - TROPICAL DEP 13 13.70 69.80 11/15/06Z 30 - TROPICAL DEP 14 14.00 69.60 11/15/12Z 30 - TROPICAL DEP 15 14.30 69.20 11/15/18Z 30 - TROPICAL DEP 16 14.60 68.80 11/16/00Z 30 - TROPICAL DEP 17 14.80 68.50 11/16/06Z 30 - TROPICAL DEP 18 15.00 68.10 11/16/12Z 30 - TROPICAL DEP 19 15.10 67.70 11/16/18Z 30 - TROPICAL DEP 20 15.30 67.30 11/17/00Z 35 - TROPICAL STO 21 15.80 66.90 11/17/06Z 35 - TROPICAL STO 22 16.70 66.80 11/17/12Z 35 - TROPICAL STO 23 13.10 70.50 11/17/18Z 35 - TROPICAL STO 24 17.50 67.90 11/18/00Z 35 - TROPICAL STO 25 18.60 68.00 11/18/06Z 35 - TROPICAL STO 26 19.10 68.50 11/18/12Z 30 - TROPICAL DEP 27 19.40 69.10 11/18/18Z 25 - TROPICAL DEP 28 19.80 69.70 11/19/00Z 20 - TROPICAL DEP 29 20.20 70.40 11/19/06Z 20 - TROPICAL DEP Bombay (BM219) 19.0 0 N 72.8 0 E