Climate scientists are making shift to a new “normal”

NIWA climate scientists are redefining what’s normal when it comes to the weather.

A team of technicians and researchers are embarking on a major project to update New Zealand’s “Climate Normals” that will take at least six months to complete.

Climate Normals are what scientists define as an average statistic based on a 30-year timespan. So when climatologists describe rainfall amounts as “above normal” or temperatures as “below normal”, they are currently comparing the figures to a 30-year average of data collected between 1981 and 2010.

Climate Normals are important because they act as a benchmark against which recent or current weather observations can be compared and are also widely used as a representation of the most likely climate conditions for a given location and time of year.

But soon “normal” will shift to the new 30-year timespan between 1991 and 2020. The change has been prompted by the World Meteorological Organization (WMO) which determines the 30-year period as the accepted statistical convention. Updating to the new 30-year time period is a requirement for all WMO member countries around the globe.

The switch won’t change any actual weather measurements, but due to our warming planet, it will mean the new temperature normal will be higher than previously.

Technological advances have also been huge in the past 30 years which has meant changes to the way data are collected.

Principal climate technician Andrew Harper says his team continually undertake field verifications of the data they are collecting and calibrate the instruments.

“This is especially important because there has been a proliferation of different types of weather stations in recent times and we need to ensure that they each measuring the variables the same way.”

Climate scientist Raghav Srinivasan says the process of changing the normal takes several steps. After site checks data must be quality controlled, audited and standardised.

One of the crucial steps is identifying and then filling gaps in the data. Gaps can be caused by a range of issues from severe weather damaging the weather station, transmitting malfunctions and something as simple as a spider web affecting the size of a hole through which rain passes into a measuring container. Filling the gaps can be done using a range of calculations partly derived from data of nearby stations.

“Even if there is a complete 30-year record we need to make sure it is good quality so we follow several processes, including auditing selected variables,” Srinivasan says.

It is a detailed and painstaking process that he likens to good housekeeping.

“It’s a chance to look back and check the data and go into the details and it’s going to take quite a few of us to achieve.

“Tracking changes over time is fundamental to climate science.”

It is expected the new Climate Normals will be ready at the end of the year.

Source:  NIWA

Commission for Agricultural Meteorology gives award for exceptional service to Dr Salinger

Jim

  

The Award for Exceptional Service has been given to Dr Jim Salinger for outstanding contributions and exceptional service to the Commission for Agricultural Meteorology (CAgM) of the World Meteorological Organization (WMO).

“Very few people receive this award so I am very honoured,” Jim told AgScience.

The commission’s role is to provide guidance in the field of agricultural meteorology by studying and reviewing available science and technology; to propose international standards for methods and procedures; to provide a forum for the examination and resolution of relevant scientific and technical issues; to promote training and the transfer of knowledge and methodologies, including the results of research, between WMO members; and to promote international cooperation.

Jim has been a member of the commission and New Zealand’s principal delegate from 1986 – 2010, and has been a member since, totalling 32 years.

During that period he chaired several CAgM working groups and expert teams, was its vice president for eight years, and was its ninth president from 2006 – 2010.  Subsequently he has chaired a task team.

“So as well as guiding the policy and work plan of CAgM for member states, I have produced many publications,” Jim said.

The most significant ones are listed below.

His next task is to provide an update of Climate Variability, Agriculture and Forestry.

KEY PUBLICATIONS:

Technical Note No. 196, 1994: Climate Variability, Agriculture and Forestry. Report of the CAgM-IX Working Group on the Study of Climate Effects on Agriculture including Forests and of the Effects of Agriculture and Forest on Climate, WMO-No. 802, 152 pp.

Technical Note No. 199, 1997: Climate Variability, Agriculture and Forestry: An Update, Salinger, M.J., Desjardins, R., Jones, M.B., Sivakumar, M.V.K., Strommen, N.D., Veerasamy, S. and Lianhai, W., WMO-No. 841, 51 pp.

Technical Note No. 200, 2000: Climate Variability, Agriculture and Forestry: Towards Sustainability, Salinger, M.J., Desjardins, R.L., Janzen, H., Karing, P,H., Veerasamy, S. and Zipoli, G., WMO-No. 928, 41 pp.

Salinger, M.J., Sivakumar, M.V.K. and Motha, R. (eds). Increasing Climate Variability and Change: Reducing the vulnerability of agriculture and forestry. Springer, Dordrecht, 362 pp. 2005.

Salinger, M.J. (ed). Climate and Oceanic Fisheries. July 2013. Special issue of Climatic Change.