Andrew Colman

• BSc General Science Newcastle Upon Tyne 1984
• Researcher at Met Office

The Greater Horn of Africa is prone to extreme climatic conditions, thus, making climate services increasingly important in supporting decision-making processes across a range of climate sensitive sectors. This study aims to provide a comprehensive review of the recent advances, gaps and challenges in the provision of climate services over the regi...

We evaluate the skill of predictions of the East African short‐rains (October–December) season, of up to 5 months lead, based on a two‐stage dynamical/statistical hybrid approach. The statistical component is a well‐established, zero‐month lead, method based on observed ocean‐scale patterns of July–September sea surface temperature. A strong advant...

Drought and food security crises heighten risks to lives and livelihoods in East Africa. In recent years, a shift towards acting in advance of such events has gained momentum, notably among the humanitarian and development community. This shift is premised on tools that link climate forecasts with pre-agreed actions and funding, known as Forecast-b...

Regional‐scale seasonal climate outlooks are typically produced using forecast information either local to the region or from another area with teleconnections to the region. Dynamical global long‐range forecast (LRF) systems can provide both types of information, and these two approaches are compared in the context of seasonal rainfall forecasts f...

The time series of monthly global mean surface temperature (GST) since 1891 is successfully reconstructed from known natural and anthropogenic forcing factors, including internal climate variability, using a multiple regression technique. Comparisons are made with the performance of 40 CMIP5 models in predicting GST. The relative contributions of t...

This chapter describes the prediction of seasonal timescale events such as seasonal means; its focus will be forecasts of 1-6 months ahead. Seasonal predictability tends to be evident on larger scales; therefore, much of the chapter discusses predictability for the three regions, including Sahel, Soudan, and Guinea coast. Most of the literature on...

The Sahel experienced a severe drought during the 1970s and 1980s after wet periods in the 1950s and 1960s. Although rainfall partially recovered since the 1990s, the drought had devastating impacts on society. Most studies agree that this dry period resulted primarily from remote effects of sea surface temperature (SST) anomalies amplified by loca...

Decadal climate predictions are now established as a source of information on future climate alongside longer-term climate projections. This information has the potential to provide key evidence for decisions on climate change adaptation, especially at regional scales. Its importance implies that following the creation of an initial generation of d...

We discuss 13 real-time forecasts of global annualmean surface temperature issued by the United Kingdom Met Office for 1 year ahead for 2000–2012. These involve statistical, and since 2008, initialized dynamical forecasts using the Met Office DePreSys system. For the period when the statistical forecast system changed little, 2000– 2010, issued for...

We discuss 13 real-time forecasts of global annualmean surface temperature issued by the United Kingdom Met Office for 1 year ahead for 2000–2012. These involve statistical, and since 2008, initialized dynamical forecasts using the Met Office DePreSys system. For the period when the statistical forecast system changed little, 2000– 2010, issued for...

The height of waves at North Sea oil and gas installations is an important factor governing the degree to which operational activities may be undertaken at those facilities. A link between the North Atlantic Oscillation (NAO) and winter (defined as December-February) wave heights at North Sea oil and gas installations has been established. A tool h...

We comment in some detail on the difficulties of correctly capturing recent Arctic warming accurately in global surface temperature data sets. We also discuss likely biases in modern sea surface temperature (SST) data worldwide and the effect these may have on assessed global temperatures The latter likely lead to a small underestimation of global...

Availability of probabilistic information of weather anomalies (e.g. temperature and precipitation) at the long-range (intra-seasonal to inter-annual timescales) can aid the decision process in a wide range of socio-economic applications. A risk-based approach should be taken in such decision-making processes because of the inherent uncertainty in...

Three prominent quasi-global patterns of variability and change are observed using the Met Office's sea surface temperature (SST) analysis and almost independent night marine air temperature analysis. The first is a global warming signal that is very highly correlated with global mean SST. The second is a decadal to multidecadal fluctuation with so...

Previous climate model projections of climate change accounted for external forcing from natural and anthropogenic sources but did not attempt to predict internally generated natural variability. We present a new modeling system that predicts both internal variability and externally forced changes and hence forecasts surface temperature with substa...

Sea-surface temperature (SST) is one of the principal factors that influence seasonal climate variability, and most seasonal prediction schemes make use of information regarding SST anomalies. In particular, dynamical atmospheric prediction models require global gridded SST data prescribed through the target season. The simplest way of providing th...

While seasonal forecasts are often presented as anomaly sign or tercile probabilities,many users are more interested in the likelihood of an extreme season. The skill of Met Office dynamical ensemble forecast systems in predicting extremes has been assessed using the LEPS skill measure and compared with overall forecast skill. Assessments of retros...

We comment on speculations in Folland et al. (2001, hereafter FCRD)about atmospheric and oceanic influences on northeast Brazil (NEB)rainfall in the austral winter dry season. FCRD was mainly concerned with the NEB wet season and its predictability. However, the paper also touched upon the dry season, particularly June and July, when there is somet...

An ensemble of twenty four coupled ocean-atmosphere models has been compared with respect to their performance in the tropical Pacific. The coupled models span a large portion of the parameter space and differ in many respects. The intercomparison includes TOGA (Tropical Ocean Global Atmosphere)-type models consisting of high-resolution tropical oc...

The predictability of rainy season rainfall over northeast Brazil for the relatively long period 1912-98 is analyzed using dynamical and empirical techniques. The dynamical assessments are based on the HadAM2b atmospheric model forced with the Met Office Global Sea Ice and Sea Surface Temperature Dataset (GISST3). Ensembles of simulations and hindc...

The predictability of rainy season rainfall over northeast Brazil for the relatively long period 1912-98 is analyzed using dynamical and empirical techniques. The dynamical assessments are based on the HadAM2b atmospheric model forced with the Met Office Global Sea Ice and Sea Surface Temperature Dataset (GISST3). Ensembles of simulations and hindc...

 The success of an ENSO-based statistical rainfall prediction scheme and the influence of ENSO on Australia are shown to vary in association with a coherent, inter-decadal oscillation in surface temperature over the Pacific Ocean. When this Inter-decadal Pacific Oscillation (IPO) raises temperatures in the tropical Pacific Ocean, there is no robust...

Statistical prediction of July–August Central England Temperature (CET) using January–February sea surface temperature anomalies (SSTA) in the North Atlantic was described by Colman (1997), Int. J. Climatol., 17, 1285–1300. In this paper, the method is extended to examine the predictability of rainfall, surface temperature and pressure in Europe. U...

There is increasing evidence of coherent patterns of variability on near quasi-bidecadal time scales in a range of climatic data from many parts of the world. Folland et al. (1984) found peaks at periods of 16 and 21 years respectively in spectra of globally- averaged sea surface temperature (SST) and night marine air temperature (NMAT) for 1856–19...

It is shown that the July–September sea-surface temperature (SST) pattern contains moderately strong relationships with the October–December (OND) seasonal rainfall total averaged across East Africa 15°S–5°N, 30°–41.25°E. The relations can be described by using three rotated global SST empirical orthogonal functions (EOFs), mainly measuring aspects...

A potentially useful predictive relationship has been found between the North Atlantic sea-surface temperature anomaly (SSTA) pattern in winter and the subsequent summer (July–August) central England temperature (CET) in England. This relationship can be seen in timewise correlation maps between CET and gridded SSTA. The SSTA pattern which correlat...

Research in several centres suggests that sea-surface temperature anomalies (SSTAs) have a strong influence on seasonal circulation in the tropics (e.g. Nicholls 1987; Shukla and Fennessy 1988; Folland et al. 1991; Ward and Folland 1991). Motivated by this suggestion, real-time experimental forecasts of seasonal rainfall in the Sahel region of Nort...

Long-range weather forecasting is a notoriously difficult area of environmental science. However, recent improved understanding of atmospheric dynamics and better observations indicate that useful progress, rooted in scientifically sound ideas, may be possible with long-range forecasting in the tropics. We describe recent research into the mechanis...