Skip to main content
SpringerLink
Log in

Seasonal and diurnal trends of surface refractivity in a tropical environment using ground-based automatic weather stations

  • Original Paper
  • Published:
Meteorology and Atmospheric Physics Aims and scope Submit manuscript

Abstract

The seasonal and diurnal trends of surface refractivity were derived using International Telecommunication Union Radio assembly model (ITU-R P.453-13) in two locations of entirely different vegetation characteristics in Nigeria. Atmospheric refractivity is a function of temperature, pressure as well as humidity. These meteorological variables were applied to the model to compute the refractivity parameter. Atmospheric refraction or refractivity is a key component in radio wave propagation. Real-time measurement data from a network of ground-based automatic weather station (AWS) installed at 3 m height were used and the monthly trends of surface refractivity at both stations (Lagos and Anyigba) were derived; the trends showed a month-to-month variability signifying the dynamic nature of the Earth’s atmosphere. The monthly trends in both stations show high refractivity values in the rainy months and low refractivity values in the dry months. A drop in refractivity value was observed in Lagos in the month of August, due to the cessation in rainfall as a result of a phenomenon referred to as August break. The diurnal variations were also determined and results obtained showed that the lowest refractivity value in the dry season observed in Lagos is higher than the highest refractivity value in rainy season observed in Anyigba. This is attributed to the fact that Lagos is located along the coast of the South Atlantic Ocean, therefore, the monsoon has a direct influence on its atmosphere, while Anyigba is an inland station with a mixture of savannah vegetation. Overall, the diurnal variations show high values in the morning and evening hours and low values in the afternoon hours in both seasons in Anyigba, while in Lagos we observed a surprising result, such as a rise in refractivity value at pre-noon and a post-noon drop. This unacquainted observation is probably due to excessive precipitation in the area caused by the influence of massive emissions from the South Atlantic Ocean, these emissions are mainly a result of the trapped heat due to warming of surface water.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Similar content being viewed by others

References

  • Adediji AT, Ajewole MO (2010) Microwave anomalous propagation (AP) measurement over Akure south-western Nigeria. J Atmos Terr Phys 72:550–555

    Article  Google Scholar 

  • Adedoyin JA (1989) Initiation of West African squall lines. Meteorol Atmos Phys 41:99–103. https://doi.org/10.1007/BF01043455

    Article  Google Scholar 

  • Adeyemi RA, Kolawale LB (1992) Seasonal and diurnal variations of surface refractivity in Akure, south-western Nigeria. Unpublished M.SC thesis depart Phys Fed Univ Tech Akure.

  • Adeyemi B, Ewetumo T (2006) Intra-layer (low level/upper layer) refractivity relations over Lagos and Kano. Global J Pure Appl Sci 12(3):403–408

    Google Scholar 

  • Ayantunji BG, Yusuf N, Osita UC (2011). Technical report on microwave propagation study over Nigeria. Presented to Federal Republic of Nigeria 22.

  • Ayantunji BG, Okeke PN, Urama JO (2011) Seasonal variation of surface refractivity over Nigeria. Adv Space Res 48(12):2023–2027

    Article  Google Scholar 

  • Ayantunji BG, Okeke PN, Urama JO, Yusuf N (2011) A semi-empirical model for vertical extrapolations of surface refractivity over Nigeria. Afr Rev Phys 6(0004):121–128

    Google Scholar 

  • Battan LJ (1973) Radar observation of the atmosphere. University of Chicago Press, Chicago

    Google Scholar 

  • Bean BR, Dutton EJ (1968) Radio Meteorology. Dover Publications Inc., New York

    Google Scholar 

  • Bech J, Magaldi A, Codina B, Lorente J (2012a) Effects of anomalous propagation conditions on weather radar observations. In: Bech J, Chau MJ (eds) Doppler radar observations. IntechOpen, London

    Google Scholar 

  • Bech J, Magaldi A, Codina B, Lorente J (2012b) Effects of anomalous propagation conditions on weather radar observations. Intech, Rijeka, pp 307–332. https://doi.org/10.5772/38172

    Book  Google Scholar 

  • Demoz B (2006) The dry line on 22 May 2002 during IHOP 2002: convective-scale measurements at the profiling site. Mon Weather Rev 134:294–310

    Article  Google Scholar 

  • Doviak RJ, Zrnic DS (1993) Doppler radar and weather observations. Academic Press, Cambridge

    Google Scholar 

  • Fabry F, Frush C, Zavadski I, Kilambi A (1997) On the extraction of near surface index of refractivity using radar phase measurements from ground targets. J Atmos Ocean Technol 14:978–987

    Article  Google Scholar 

  • Falodun SE (2004) Experimental studies of super-refraction of microwave signal. Unpublished PhD Thesis Depart Phys Fed Univ Tech Akure.

  • Falodun SE, Ajewole MO (2006) Radio refractive index in the lowest 100m layer of the troposphere in Akure. South-western Niger J Atmos Terr Phys 68:236–243

    Article  Google Scholar 

  • Falodun SE, Kolawale LB (2000) Studies of super-refractivity and ducting of radio waves in Nigeria. Niger J Appl Phys 1:5–10

    Google Scholar 

  • Fritz J, Chandrasekar V (2009) Implementation and analysis of networked radar refractivity retrieval. J Atmos Ocean Technol 26:2123–2135

    Article  Google Scholar 

  • Fornasiero AP, Alberoni P, Bech J (2006) Enhanced radar precipitation estimates using a combined clutter and beam blockage correction technique. Nat Hazards Earth Syst Sci 6:697–710

    Article  Google Scholar 

  • ITU-R (2013) The radio refractive index: its formula and refractivity data. Recomm ITU-R 453:13

    Google Scholar 

  • IPCC 2008. Intergovernmental Panel on Climate Change Fifth Assessment Report (AR5). 28th Session (09–10 April 2008, Budapest, Hungary). https://www.ipcc.ch/report/ar5/. Retrieved 22 July 2019

  • Jacques P, Boudjabi C, Besson CL, Caumont O (2012) Errors caused by long-term drifts of magnetron frequencies for refractivity measurement with a radar: theoretical formulation and initial validation. J Atmos Ocean Technol 29(10):1429–1434

    Google Scholar 

  • Kolawale LB, Owunobi JJ (1982) The surface radio refractivity over Africa. Niger J Sci 16(1–2):441–454

    Google Scholar 

  • NIMET, 2012. The 2012 Nigeria Climate Review Bulletin. (https://nimet.gov.ng/publication/annual-climate-review-bulletin-2012). Retrieved 22 July 2019

  • Oyedum OD, Gambo GK (1994) Surface radio refractivity in northern Nigeria. Niger J Phys 6:36–41

    Google Scholar 

  • Oyinloye JO (1987) The troposphere in tropical and sub-tropical latitudes. Handbook on radio propagation for tropical and sub-tropical countries. URSI Comm Dev Count

  • Prtenjak MT, Horvat II, Tomažić M, Kvakić M, Viher M, Grisogono B (2015) Impact of mesoscale meteorological processes on anomalous radar propagation conditions over the northern Adriatic area. J Geophys Res Atmos 120:8759–8782. https://doi.org/10.1002/2014JD022626

    Article  Google Scholar 

  • Prospero JM, Lamb PJ (2003) African droughts and dust transport to the Caribbean: climate change implications. Science 302:1024–1027

    Article  Google Scholar 

  • Rüeger JM (2002) Refractive index formulae for electronic distance measurement with radio and millimeter waves. In: Unisurv Report S-68, School of surveying and spatial information systems, vol 2052. University of New South Wales, UNSW SYDNEY NSW, pp 1–52

    Google Scholar 

  • Smith EK Jr, Weintraub S (1953) The constants in the equation for atmospheric refractive index at radio frequencies. Proc IRE 41:1035–1037

    Article  Google Scholar 

  • Thayer GD (1974) An improve equation for the radio refractive index of air. Rad Sci 9(10):803–807

    Article  Google Scholar 

  • Viher M (2006) A study of the modified refraction indices over the Alpine and sub-Alpine region. Meteorologische Zeitschrift (Meteorologist Festschrift) 15:625–630

    Article  Google Scholar 

  • Viher M, Kos T, Markezic I (2011) A study of the maximal height for the exponential model of the refractivity Index vertical profile in the Republic of Croatia. In: Proceedings of the 53rd International Symposium Electronics in Marine (ELMAR), pp 187–190.

  • Viher M, Prtenjak MT (2012) A multi-year study of radio-wave refractivity profiles above the Adriatic Sea up to an altitude of 40 km. Meteorol Zeitschrift 21:365–370

    Article  Google Scholar 

  • Viher M, Prtenjak MT, Grisogono B (2013) A multi-year study of the anomalous propagation conditions along the coast of the Adriatic Sea. J Atmos Solar Terr Phys 97:75–84. https://doi.org/10.1016/j.jastp.2013.01.014

    Article  Google Scholar 

  • Wait JR (1962) Electromagnetic waves in staratified media. Pergamon Press, Oxford

    Google Scholar 

  • Wakimoto RM, Murphey HV (2010) Frontal and radar refractivity analyses of the dry line on 11 June 2002 during IHOP. Mon Weather Rev 138:228–240

    Article  Google Scholar 

  • Yusuf Najib, Okoh D, Musa I, Samson A, Rabia S (2017) A Study of the surface air temperature variations in Nigeria. Open Atmos Sci J 11:54–70. https://doi.org/10.2174/1874282301711010054

    Article  Google Scholar 

Download references

Acknowledgements

The results presented in this paper rely on TRODAN data collected and managed by the Centre for Atmospheric Research, National Space Research and Development Agency, Federal Ministry of Science and Technology, Anyigba, Nigeria. We thank the Centre for Atmospheric Research and their partners for promoting high standards of atmospheric observatory practice as well as the Federal Government of Nigeria for continuous funding of the Nigerian Space programme (http://www.carnasrda.com).

Author information

Authors and Affiliations

  1. NASRDA’S Centre for Atmospheric Research (CAR), Kogi State University Campus, P. O. Box 380, Anyigba, Nigeria

    Najib Yusuf

  2. Department of Physics, Micheal Okpara University, Umudike, Nigeria

    O. E. Ekpe

  3. Department of Physics, Bayero University, Kano, Nigeria

    Najib Yusuf & Rabia S. Said

  4. Department of Policy, Planning and Research, National Space Research and Development Agency, Abuja, Nigeria

    B. G. Ayantunji

  5. Department of Industrial Physics (Astrophysics Unit), Ebonyi State University, Abakaliki, Nigeria

    A. E. Umahi

Authors
  1. Najib Yusuf
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. O. E. Ekpe
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Rabia S. Said
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. B. G. Ayantunji
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. A. E. Umahi
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Najib Yusuf.

Additional information

Responsible Editor: M. Telisman Prtenjak.

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Yusuf, N., Ekpe, O.E., Said, R.S. et al. Seasonal and diurnal trends of surface refractivity in a tropical environment using ground-based automatic weather stations. Meteorol Atmos Phys 132, 327–340 (2020). https://doi.org/10.1007/s00703-019-00693-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00703-019-00693-6

Search

Navigation