Green walls and roofs

A green wall is a wall which is covered (totally or partially) with vegetation or an inorganic growing medium.

A green roof is planted on top of a waterproof membrane.

As well as providing non-mechanical cooling green walls and roofs increase biodiversity.

Green walls provide a layer of insulation and the process of plant transpiration brings evaporative cooling to the building.The image on the right shows what the front of the Met Office HQ would look like with a green wall.

Installing a green wall and roof represents a substantial financial outlay and although not economically viable at the moment, this idea is reviewed regularly.

It is hoped that a green wall and roof may be economically viable in the not too distant future.

Chicago City Hall (c) City of Chicago / GRC

Photovoltaic (PV) cells

A Photovoltaic (PV) or Solar Cell is an electrical device which converts sunlight directly into electricity.

In 2008, we investigated the possibility of a PV array across part of our roof but costs were deemed to be prohibitive.

Since the original study we have installed the Monsoon Supercomputer which runs on DC electricity, the same type of electricity generated by solar cells.

The idea of installing an array of PV cells will be kept under review.

Mercury replacement program.

Mercury (Hg) is deemed to be the best material to be used in meteorological thermometers.

The Met Office has around 1750 Hg thermometers.

Mercury thermometer

Hg is a very hazardous material, both to humans and the to the environment and EU legislation has banned it for domestic and health use.

Despite an exemption for scientific use we have initiated a Mercury replacement program.

We have a duty of care to all those who handle our thermometers.

The replacement program will have a phased approach. It would not be practical to stop using Hg immediately.

We need to be able to accurately measure temperatures and the replacement for HG must accurately record temperatures in a wide range of environments.

Recently we have been trialling Liquid in Glass safety thermometers on the research ship Ernest Shackleton. It returned from the Antarctic in Spring 2011 and initial results look promising.

Hydrogen fuel cells (HFCs)

Hydrogen Fuel Cell trial at Camborne

HFCs, are deemed to produce clean, quiet and efficient power, producing only water vapour as waste.

HFCs combine Hydrogen and Oxygen to produce electricity, heat and water.

In early 2010 we successfully trialled the use of a HFC as a standby generator at our RADAR training site in Exeter.

Summer 2011 we successfully trialled a HFC for a month at Camborne.

Met Office experiments often take place in remote locations for short periods of time.

For such experiments the hiring of a commercial HFC is an attractive option.

Helium shortages.

We use helium to fill the balloons which lift our radiosondes into the atmosphere.

Helium is roughly 10 times the price of hydrogen.

It is estimated that the earth has only 25 years of helium reserves left.

The Met Office does not want to rely on a gas which is in very short supply.

We are considering switching back to hydrogen to fill our weather balloons.

The main problem with this is that hydrogen is an extremely flammable gas and there are H&S implications with this.