Description

PARAMETERS

Black Sea Climatic Maps are prepared for the following oceanographic parameters:

Hydrophysical parameters

 

Hydrochemical parameters

 

UNDERLYING DATA

The data source for the Black Sea Climatic Maps  is the Oceanographic Data Bank for the Black Sea of the Marine Hydrophysical Institute, National Academy of Sciences of Ukraine, Sevastopol. The Data Bank includes data on more than 158 thousands hydrological and about 34 thousands hydrochemical stations in the basin acquired by research vessels of different countries and organizations since 1890 till 2007.

CALCULATION METHODS

Climatic fields are computed from the individual observations in the following manner:

·All quality controlled observations are averaged into the raw monthly values in each box of 20'x30' for each month during appointed period on the depth intervals: 5 m to 100 m, 10 m to 300 m, 50 m to 1000 m, 100 m up to the bottom.

·The raw monthly fields are objectively analyzed on a regular grid of 20’x30’ for each month in layer 0-200 m and annually for layers deeper than 200 m.

  The vertical interpolation method was adopted from Reiniger, Ross (1968) which represents a combination of weighted parabolas and linear interpolation. The objective analysis scheme used is similar the scheme described by Levitus (1982) and Silva, Young, and Levitus (1994). This is an iterative difference-correction scheme (Cressman, 1959) with a weight function developed by Barnes (1954). That is

with the weight function

where

g = interpolated value

f = raw value

l = iteration number

t =  time

r = distance

K = radius of influence

V = temporal radius

 

A first guess was computed as

  To filter out spatial noise a 5-point nonlinear median filter (Beaton and Tukey, 1974) followed by two passes of a 5-point linear filter (Shapiro, 1970) was applied. The first guess was determined with a radius of influence of 128 NM. The objective analysis scheme repeated twice with radii of influence of 64 and 32 NM.

Density was calculated as density anomaly γ in accordance with [1]:

 

γ =r (S,T,0) – 1000; [kg/m³]

where

r (S,T,0) = r_w +L·S + m·S ^3/2 + n·S ²;

 

r_w =999.841594+6.793952·10^-2T-9.09529×10^-3T²+1.001685×10^-4T³-1.120083×10^-6T⁴ +6.536332×10^-9T⁵;

L = 8.24493×10^-1-4.0899×10^-3T+7.6438×10^-5T²-8.2467×10^-7T³+5.3875×10^-9T⁴;

m = -5.72466×10^-3+1.0227×10^-4T-1.6546×10^-6 T²;

n = 4.8314×10^-4;

T – temperature, °C

S – salinity, PSU.

 

Heat storage or enthalpy was computed as integral:

 

C = ;

where:

ρ – density;

c - specific heat;

T – temperature;

z – depth.

 

Limits of integration were chosen as 0-100 m to emphasize seasonal evolution of cold intermediate layer, one of the Black Sea particularities.

Dynamic height, in accordance with the general usage in Soviet oceanography [2] was calculated as integral:

 

H = ;

 

where:

Vt = (α – 0.9)·103 (conventional specific gravity);

α = 1/ρ (specific gravity);

p = pressure;

 

Reference level of 300 db as the prevailing level in the Black Sea oceanography was accepted for computing dynamic topography.

 

QC PROCEDURES

Metadata Control includes the following:

- duplicate cruises and profiles check;

- data and chronology check;

- ship velocity check;

- location check;

- sea depth check;

- observation depth check.

Duplicate cruises check includes:

- check of same ship name and cruise number;

- check of cruises with same dates;

- visual check of superposed stations.

Check for duplicate profiles includes:

- automatic check of same stations positions and date (within 1 mile, 1 hour)

- visual check of the position maps of cruises

- visual check and comparing on one plot.

Data and Chronology check includes the following:

- The day must be between 1 and the number of days of the month.

- The month must be between 1 and 12

- The date and time of the profiles must be within the cruise duration.

Ship velocity check: the vessel speed between subsequent stations should not exceed the maximum for the given vessel (including the period for stations accomplishing), otherwise the visual check of stations positions/times is done.

Hydrographic Data Control includes the following:

•         density inversion check (Hydrological data are checked for detection of density inversion. Such errors are to be checked visually);

•         spikes check (Using the IOC check procedure and taking into account the difference not only in values but in gradients too. In general the spike test requires visual validation);

•         climatic check.

All data are checked to be within 3 Mean Standard Deviation from the mean. Data that have not passed this check were checked and corrected manually using visualization tools.

Oceanographic Data Quality Check software

provides:

• Both automatic and visual metadata check;
• Both automatic and visual Temperature and  Salinity check;
• Possibilities for metadata and data values correction during each step of the quality check process.

 includes:

• High quality temperature and salinity climatic arrays for the Black Sea;
• Data sets of the Black Sea depths on 1×1 miles grid (for sea depth and observation depth check);
• High-resolution array of geographic coordinates of the Black Sea shore (for station location check).

 

CREDITS

Preparation of the Black Sea climatic maps for the in-situ oceanographic parameters was done in framework of the Joint Reasearch Activity 6 (JRA6) of the EU SeaDataNet Project as a common effort of the following partners: IMS METU, Turkey (coordinator), IES-JRC (Italy), RIHMI-WDC (Russia), MHI-DMIST (Ukraine), IO-BAS (Bulgaria), NIMRD (Romania), TSU-DNA (Georgia).

Calculation of grids and maps was carried out by scientists from the Marine Hydrophysical Institute (MHI), National Academy of Sciences of Ukraine, Sevastopol: Dr. V. Belokopytov, Dr. A. Khaliulin, Sc. E. Godin, Sc. A. Ingerov

 

REFERENCES

1. Algorithms for computation of fundamental properties of sea water.  UNESCO technical papers in marine science.,  1983, № 44.

2. Zubov N N., Mamayev O.I. Dynamic method of calculating sea currents (in Russian). – Leningrad, Gidrometeoizdat, 1956, 112 pp.

3. Levitus, S.: Climatological Atlas of the World Ocean, 1982: NOAA Prof. Paper No. 13 , U.S. Government Printing Office, Washington D.C., 173 pp.

4. Cressman, G.P., 1959: An operational objective analysis scheme: Mon. Wea. Rev., No 87, 329-340.

5. Barnes, S.L., 1964: A technique for maximizing details in numerical weather map analysis. J. Appl. Meteor., No 3, 396-409.

6. Beaton, A.E., and J.W.Tukey, 1974: The fitting of power series, meaning polynomials, illustrated on band-spectroscopic data. Technometrics, No 16, 147-185.

7. Shapiro, R., 1970:  Smoothing, filtering and boundary effects. Rev. of Geophys. and Space Phys., No 8, 359-387.

8. Silva, A.M., Young C. C. and S. Levitus, 1994: Atlas of surface marine data. NOAA Atlas NESDIS, Washington, D.C.

9. Eremeev V.N., Suvorov A.M., Khaliulin A.Kh., Godin E.A. Oceanographic Data Development for Anoxic Zone Boundary in the Black Sea. Proceedings of the NATO Advanced Research Workshop on Integrated Approach to Environmental Da-ta Management Systems, Bornova, Izmir, Turkey, September 16-20, Kluwer Academic Publishers Dordrecht /Boston/ London 1997

10. Unesco 1993: Manual of quality control procedures for validation of oceanographic data, IOC UNESCO, pp.436.