Press release from ERL: 2 readings - PowerPoint Presentation

Slide1

Press release from ERL: 2 readings

1.

2

.

MotivationShips are strong sources of greenhouse gases and air pollutants:

3% of global CO2 emissions±13% of global

NOx emissions (5-20%)±12% of global SO2

emissions

IMO, 2014

MotivationShipping sector shows a degree of awareness

Claims to be a relatively clean mode of transportationReduce emissions by speed reductions and other measures

Ship CO

2

efficiencies

MotivationLegal framework to reduce ship emissions slow in makingIMO initiatives to implement NECA and SECA

I

mplemented in US waters in 2016

2000

2011

Very few measurements on open sea OMI overpass time: 13:40 hrs

Estimating NOx

emissions from NO2 observations

Lifetime of NO

2 at noon is generally short (few hours)Close relationship between NOx emissions and local NO2 columnsS

imple mass balance approach (Martin et al. [2003]):

Practical difficulties:

Standard CTM chemistry

not appropriate for

plumes

Emissions may be misplaced (

E

apriori

)

E

apriori

:

N

CTM

varies in time and space (non-linear local chemistry)

Smearing, weak signal (poster

Huan

Yu)

NO

2

column measured by OMI

NO

2

column simulated by CTM

Emission inventory used in CTM

1. Account for plume chemistry in GEOS-Chem

GEOS-

Chem

plume-in-grid approach for ship emissions

Higher OH in early stages of the plume

Improved simulations with plume-in-grid show 50% lower

NO

x

concentrations than instant dilution!

Vinken

et al., ACP, 2011

OH

NO2

t

2. Detecting

emission patterns with OMI

OMI shows that EMEP emissions are misplaced

(2.5 Tg NO

2

)

(3.7 Tg NO

2

)

3. Account for non-linear chemistry in providing constraints on emissions

Satellite

Model

3

4

1

2

3

4

1

2

β describes local, monthly mean clear-sky sensitivity of NO

2

columns to (changes in)

NO

x

emissions

(

Lamsal

)

For clear-sky European Seas:

β = 0.5-1.0 (0.7)

4. Avoid smearing

Select days

without clouds

and

without outflow

of continental pollution

NO

x emission estimates

ships in Europe: 2005

before

OMI top down inventory

(0.9

Tg

N/

yr

)

Changes in 2005-2012 ship

NOx emissions over European Seas (in

TgN yr-1

)4 lanes represent 30% of European shipping NOx emissions

Estimates mostly based on Spring & Summer observations

Increase from 2005-2008, then decrease in 2009

NOx pollution from ships increasing in relevance

Annual changes in

NO

x emissions (2005-2008)Changes inferred from OMI by Curier et al. [2014]

Changes inferred from OMI in this work

Comparison to changes in economic indicators

No net change in European ship

NOx emissions between 2005 and 2012Increase in share of shipping sector to NOx emissions from 1 in 9 to 1 in 7

Slow steaming?

Economic recession in Autumn 2008; shipping sector responded

Cutting costs by saving on fuelReducing overcapacity (less demand)

Slow steaming:Reducing vessel speed from 20-25 knots to 16-19 knotsThis would reduce CO2 and NOx

emissions

Slow steaming observed from space1. Long-term data set (1992-2012) of ship presence detected by satellite altimeter instruments

2

. Registration of the number of ships passing the Suez Canal

Slow steaming from space:

Mediterranean Sea

Slow steaming from space

N

umber of ships through the Suez Canal relatively constant

Number of ships detected over Mediterranean increasesIndication for a longer residence time in the MediterraneanRatio Suez : altimeter ~ ship speed

Ratio OMI

NOx

: altimeter ~

per ship emission factor

Normal

(20-25 knots;

37 – 46

km/

hr

)

Slow

steaming

(14-

20 knots;

25 – 37 km

/

hr

)

SummaryOMI allows detection of ship emissions on open sea

European ship NOx emissions increased from 2005-2008Back at their 2005 levels in 2012 (in line with trade)

Because land-based emissions decreased by 25%, ship emissions now make up a larger fraction (1 in 7) of European NOx emissions

Direct evidence of slow steaming from altimeter in combination with Suez Canal passagesShip speeds reduced by 30% in the MediterraneanAccompanied by large NOx emission reductions

21

st

century

ECA’s will be enforced in 2016

Demand will increase

Oil will still be used as fuel