1. Associate Research Professor of Physical Oceanography
Sea Level Variations &
Sea Level Rise (SLR)
Dr. Tarek M. El-Geziry
Associate Research Professor of Physical Oceanography
Laboratory of Physical Oceanography
Division of Marine Environment
National Institute of Oceanography & Fisheries (NIOF), Egypt

2. Summary of Today’s Talk
The Sea Level, is it Tides?
Distances & Declinations
Tidal Constituents
Sea Level Variations
BREAK
Climate Driving Forces
Sea Level Rise (SLR)
Risk Management

3. The Sea Level, is it Tides?
At any location, the observed sea level is the sum of two different components: the astronomical tides (celestial impact) and the residual sea level (surge); in addition to the Mean Sea Level (MSL).

4. The Sea Level, is it Tides?

5. Distances and Declinations

6. It takes 365 ¼ days for the Earth to move from one perihelion to another, i.e. one cycle every year
1. The Earth-Sun System
At perihelion phase, the tidal generating force is larger than average. This means greater tidal ranges are observed.
At aphelion phase, the reverse is true. (

7. 2. The Earth-Moon System
The perigee phase has the greater effect on the observed tidal range than the apogee phase.
From a perigee to another, the moon revolves in days, i.e. a lunar month. (

8. It takes the moon about 1 month (29 ½ days) to go through the phases

9. 2. The Earth-Moon System The Lunar Day(

10. (http://www. signsinlife. com/wp-content/uploads/2011/12/declination(

11. The plane of the moon’s orbit declines 5
The plane of the moon’s orbit declines 5.14o to the Ecliptic plane system of Earth-Sun, and not to the Equator.
The monthly declination of the moon will range between Earth’s declination around its axis +/- declination of the moon’s plane to the ecliptic.
SO, we have the maximum monthly declination o o = o, and the minimum monthly declination o – 5.14o = o .
This results in unequal diurnal variations of tides over the Earth, and gives the three major patterns of tides.

12. Pinet (2005)

14. Tidal Harmonic Constituents
Each one of the tide-generating motions, represented by a simple
harmonic cosine curve, is known as a tidal component, tidal constituent, or harmonic constituent.
A letter or letters and usually a subscript is used to designate each constituent.
The Principal Lunar semidiurnal constituent is designated M2. M is for moon, of course, and the subscript 2 means that there are two complete tidal cycles for each astronomic cycle.
Thus, this is said to be a semidiurnal constituent.

15. Tidal Harmonic Constituents
Constituents are described by their tidal period (the time from maximum to maximum), T.
The period for the S2 is solar hours (hr.) and the period for the M2 is solar hours.
In tidal work, each constituent (cosine curve) is more often described by its speed (or frequency in degrees per hour).
The cosine curve is divided into 360° (from crest to crest). The speed, n, of the constituent is 360°/T.
Thus, for S2, n = 360°/12.00 = 30°/hr.
For M2, n = 360°/ = °/hr.

16. Tidal Harmonic Constituents
Principal lunar M2
100
12.42
Principal solar S2 46
12.00
Larger lunar elliptic N2 19
12.66
Luni-solar semidiurnal K2 13
11.97
Larger solar elliptic T2
12.01
Smaller solar elliptic L2
12.19
Lunar elliptic second order
2N2
12.91
Luni-solar diurnal K1 58
23.93
Principal lunar diurnal O1 42
25.82
Principal solar diurnal P1
24.07
Large lunar elliptic Q1
26.87
Smaller lunar elliptic M1
24.84
Small lunar elliptic J1
23.10
Lunar fortnightly Mf 17
327.86
Lunar monthly Mm
661.30
Solar semi-annual
Ssa
Pugh (1987)

17. Tidal Harmonic Constituents

18. Impact of the Storm Surge over Alexandria in December 2010
Residual component
Impact of the Storm Surge over Alexandria in December 2010

21. Climate Change/Climate Variability
Vulnerability

22. Impact of Climate Change
Dry Regions
Higher Air Temperature
More Ocean Acidity
Warmer Oceans
Changes in
Rainfall Patterns
Accelerated Rising
Sea Level Rates

23. Intergovernmental Panel on Climate Change (IPCC)

24. Definitions of Scenarios
A1F1
Fossil Fuel
Intensive Use
A1B
Balanced
Use of
Resources
A1T
Non Fossil
Fuel A2
Atmospheric Stabilization Framework (ASF) B1
Model for Energy Supply Strategy Alternatives & Green Environment (MESSAGE) B2
Integrated Model to Assess Greenhouse Effect (IMAGE)

25. Intergovernmental Panel on Climate Change (IPCC)
Representative Concentration Pathways (RCP)
(IPCC, 2014)

26. Definitions of rcps Total Control on the Greenhouse Gas Emissions
Stabilization at the Present Rates of Emissions
RCP6.0
More Greenhouse Gas Release but Still Under Control
RCP8.5
More Greenhouse Gas Release With NO CONTROL

27. Relative Sea Level Rise
SEA LEVEL RISE (SLR)
Global Sea Level Rise
Sea Level Rise (SLR)
Relative Sea Level Rise

28. Causes of the Global SLR
~50% of the GSLR since
1993
~25% of the GSLR
( )
30% of the GSLR ( )

29. The Two Major Factors Acting on SLR
Ice Melt
More Water, More Mass 
Thermal Expansion, More Volume
Heat 
SLR

30. Sea Level Budget Changes With Time
3.2 mm/yr
1.8 mm/yr
1.7 mm/yr
1.5 mm/yr
1.3 mm/yr
0.5 mm/yr
Volume
Mass
Total
Volume
Mass
Total
(Miller, 2008)

31. Tools to Detect & Investigate the GSLR
SEA LEVEL RISE (SLR)
Tools to Detect & Investigate the GSLR
Long-term Tide Gauge Data Sets
Global Satellite Altimetry
Atmosphere-Ocean General Circulation Model (AOGCM)
Projections from the IPCC Scenarios

32. SLR from Topex & Jason-1: 1993-2007
GLOBAL SEA LEVEL RISE IS NOT GLOBALLY UNIFORM!!
SLR is spatially highly non-uniform

33. (https://robertscribbler(

34. Projected global averaged surface warming
and sea level rise till 2100, IPCC-2007
Sea Level Rise
(m)
Temperature Change (oC)
Scenario
1.8
2.4
2.8
3.4
4.0
B1 Scenario
A1T Scenario
B2 Scenario
A1B Scenario
A2 Scenario
A1F1 Scenario

35. The Fourth Assessment Report (AR4, IPCC 2007) projected that global mean sea level will rise up to 60 cm by 2100 in response to ocean warming and glaciers melting (in the worst scenario, A1F1)
This projection rose (AR5, IPCC 2014) to range between 52 and 98 cm by the year 2100 under the RCP8.5 scenario and between 28–61 cm under the RCP2.6 scenario.

36. Causes of the Relative Sea Level Change
The relative sea-level change is the change that can be measured by a tide gauge at specific coastal locations.
Rise & Fall of Sea Surface
Rise & Subsidence of Land
Relative sea-level change is the most important measurement in terms of assessing the SLR impact on infrastructure, properties and ecosystems.
Waves & Currents Climatology
Erosion & Accretion
The most vulnerable environments to the SLR are Deltas, estuaries, barrier islands and coral reef communities.
Natural & Anthropogenic Factors

37. Between 1960 and the beginning of the 1990s cooling of the upper waters of the eastern Mediterranean basin, associated with increased atmospheric pressure caused reduction in the relative sea level rise.

38. Rate of Relative SLR (cm/yr)
WHAT ABOUT EGYPT?
Authors
Period (years)
Rate of Relative SLR (cm/yr)
El-Fishawi and Fanos (1989) 23
0.290
Frihy (1992)
44 ( )
0.200
UNSECO (2003)
Frihy (2003)
55 ( )
0.160
Shaker et al. (2011)
20 ( )
0.170
Maiyza and El-Geziry (2012)
33 ( )
0.212
Said et al. (2012)
37 ( )
0.300

39. WHAT ABOUT EGYPT?
(Fitzgerald et al., 2008)

40. WHAT ABOUT EGYPT?
Predicted SLR values at several locations in 2025, 2050, 2075 and 2100 using B1 (left) and A1FI (right) SLR scenarios (Roushdi, 2012)

41. WHAT ABOUT EGYPT?
Predicted inundated areas at Alexandria and Port Said (with and without protection) (Roushdi, 2012)
The economic loss is estimated to be ~60x109 EGP for Agricultural Lands & ~20x109 EGP for Urban Land Areas

43. RISK MANAGEMENT

44. RISK MANAGEMENT
The location of the 136 port cities analysed in Nicholls et al. (2008)
A key result of the study is that socio-economic changes are the most important driver of the overall increase in population and asset exposure and that climate change, land subsidence and flooding have the potential to significantly exacerbate this effect.

45. RISK MANAGEMENT
Without adaptation, it is estimated that 0.2–4.6 % of the global population will experience flooding annually in 2100 with a SLR of 25–123 cm; global gross domestic product is expected to have a 0.3–9.3 % annual loss (Hinkel et al., 2014).
Boettle et al. (2016) showed that the coastal socio-economy sector is highly affected by coastal flooding and concluded that the damage in the socio-economical sector typically increases faster than the SLR itself.

46. RISK MANAGEMENT
Population in the LECZs (defined as lands with an elevation <10 m relative to present sea-level) (Galassi and Spada, 2014)

47. RISK MANAGEMENT
(a) Frequencies of Surge Level Height (SLH) > 0.4 m along the East Mediterranean region in 2000–2004 and (b) maximum heights for the same area in 2004 (Krestinitis et al., 2011)

48. MITIGATION Regional Specialized Meteorological Centres (RSMCs; WMO)
Tropical Cyclone Warning Centres (TCWCs; WMO)
Calculations of Risk and Return Periods of Extremes
Buckman et al. (2015) developed the Global Storm Surge Forecasting and Information System as the first-of-its-kind operational forecasting system for storm surge prediction on a global scale, taking into account tidal and extra-tropical storm events in real time. The system provides real-time water level and surge information in areas that currently lack local storm surge prediction capability.

49. Design lifetime (year)
MITIGATION
Design lifetime (year) 50
100
200
300
400
500
Design risk
0.40
0.64
0.87
0.95
0.98
0.99
Design Lifetime & Risk calculated for Alexandria, based on SL data ( ) (Said et al., 2011)

50. Dr. Tarek Mohamed El-Geziry