Вестник Каспия №4/2008 Caspian Sea Bulletin От Редакции журнала «Вестник Каспия»

Introduction

The Caspian Sea is the biggest enclosed body of water on Earth, with a coastline approximately seven thousand kilometres long. Situated in a natural depression, below mean sea level, it receives water from freshwater inputs, but has no opening to the oceans. The Caspian Sea is subject to significant water level fluctuations which have had serious consequences for the region, displacing thousands of shoreline inhabitants, destroying investments in industry and infrastructure. Sea level in the Caspian Sea is clearly a topic of public concern to all five surrounding countries (Azerbaijan, Republic of Iran, Kazakhstan, Russian Federation and Turkmenistan). In addition to the danger posed to oil fields and coastal infrastructure, the water level fluctuations result in changes in a number of processes such as: water regime; dynamics and chemical composition of groundwater; structure and productivity of biological communities in the littoral [3, 6].

The network of operating stations along the coast of the Caspian Sea has sharply declined to such an extent that many areas are no longer monitored. The present situation is that the sea level station infrastructure is in a very poor state and is continuing to deteriorate, having an impact on strategic planning and management decisions at both national and regional levels (Fig.1). As a result, the infrastructure is obsolete and, in many cases, the level of technical expertise is very low. There is pressing need for improved systematic sea level

(a)

(b)

Рис.1. Вид уровнемерного поста (а) и измерительного оборудования (б) в Баку.

observations with high accuracy and resolution in the Caspian Sea and for the creation of a regional database as a basis for a reliable assessment of changes and sound scientific research. There is also a need for correct operation of sea level stations to ensure data quality and reliability. At present, no stations are maintained to GLOSS standards and therefore none is really usable for satellite altimetry calibration. In addition, no cross national uniform geodetic levelling network exists along the coasts. The consequence is that the measurements of sea level at different sites are not comparable.

The ALTICORE initiative and synergies

This report describes a field mission to install a pilot sea level monitoring station at Port Absheron, Baku, Azerbaijan (Fig.3, 4), that was held on 8-13 June 2008. The intention of this technical mission was (1) to deploy a bottom pressure owned by LEGOS at the site identified during a previous inspection visit in September 2007; (2) to perform a geodetic levelling campaign, including GPS measurements at land and sea. It is expected that we will be able (1) to collect an accurate record of in situ sea level measurements at high temporal resolution; (2) to assess the impact of local conditions in terms of weather and morphology; (3) to decide if the site is good candidate for installation of a permanent calibration/validation (cal/val) site for satellite altimetry.

Fig. 2. Satellite altimetry ground track coverage from Jason-1 (a), Envisat (b), GFO (c) and Topex/Poseidon (2002-2005) (d) in the Caspian Sea.

Рис.2. Треки спутников Jason-1 (a), Envisat (b), GFO (c) и

Topex/Poseidon (2002-2005 гг.) (d), проходящие по акватории Каспийского моря.

(source Virtual Earth).

Рис.3. Спутниковое изображение порта Апшерон (указано стрелкой) и моста на о. Пиралахи (Артем).

Fig.4. View of Port Absheron.

Рис.4. Вид Апшеронского порта.