Prediction of Indian summer monsoon: Status, problems and prospects

In this article, we review the present status and problems and future prospects of long-range forecasts of Indian summer monsoon. Since 1988, the India Meteorological Department has been issuing forecasts based on 16-parameter power regression and parametric models. All these forecasts are proved to be reasonably correct. However, in some years, forecast error was larger than the model error of ± 4. In 2000, four new promising predictors were introduced in the operational models. Using an empirical model with 100 years of data (1901-2000), we show that Indian summer monsoon predictability exhibits epochal variations. During the recent years the model is showing poor forecast skill due to weakened coupling between the boundary forcing and Indian monsoon. In spite of serious efforts by the modelling groups, there are still problems in the dynamical predictions of Indian monsoon. Prediction of Indian monsoon variability is found to be sensitive to the initial conditions, suggesting that chaotic internal dynamics may ultimately limit the predictability of Indian summer monsoon

Powering Systems From Ambient Energy Sources

Ambient intelligence and the Internet of Things will require flexible and energy efficient hardware platforms to implement the long-term deployed wireless devices that form the physical substrate for these emerging cyberphysical systems. Energy harvesting from environmental sources such as light and mechanical vibration can extend battery life for devices as long as efficient power management circuits are available. Self-timed circuits, power-on resets, integrated switched-capacitor DC/DC converters and adaptively-biased linear regulators are complementary circuit techniques that can reduce cost and power consumption for microwatt energy harvesting and energy scalable systems. Low power and low voltage analog and digital circuits for sampling, digitizing, and processing external signals are essential for powering systems from ambient energy sources. This talk presents an overview of these topics and describes how exploiting the relationship between system requirements, circuits, and environmental energy sources can enable the emergence of the Internet of Things

Writing and Politics: A Few Passing Remarks

Panel: Writing and Politic

Writing Sample

Includes r/e/c/y/c/l/i/n/g, HOMEWARD, To the conscience-keepers, Anatomy, and He Who Was Gone Thus

Is there regime behavior in monsoon convection in the late 20th century?

Mixture model techniques are applied to a daily index of monsoon convection from ERA‐40 reanalysis to show regime behavior. The result is the existence of two significant regimes showing preferred locations of convection within the Asia/Western‐North Pacific domain, with some resemblance to active‐break events over India. Simple trend analysis over 1958–2001 shows that the first regime has become less frequent while the second becomes much more dominant. Both undergo a change in structure contributing to the total OLR trend over the ERA‐40 period. Stratifying the data according to a large‐scale dynamical index of monsoon interannual variability, we show the regime occurrence to be strongly perturbed by the seasonal condition, in agreement with conceptual ideas. This technique could be used to further examine predictability issues relating the seasonal mean and intraseasonal monsoon variability or to explore changes in monsoon behavior in centennial‐scale model integrations

A high resolution daily gridded rainfall dataset (1971-2005) for mesoscale meteorological studies

In this communication, we discuss the development of a very high resolution (0.5° 0.5°) daily rainfall dataset for mesoscale meteorological studies over the Indian region. The dataset was developed using quality-controlled rainfall data from more than 3000 rain gauge stations over India. The analysis consists of daily rainfall data for all the seasons for the period 1971-2005. A well-tested interpolation method (Shepard's method) was used to interpolate the station data into regular grids of 0.5° 0.5° lat. long. After proper validation, it has been found that the present dataset is better compared to other available datasets. A few case studies have been shown to demonstrate the utility of the dataset for different mesoscale meteorological analyses. However, since the data density is not kept uniform, there is a possibility of temporal inhomogeneity and therefore, the present dataset cannot be used for trend analysis. The dataset is freely available from the India Meteorological Department, Pune

Inter-annual relationship between Atlantic sea surface temperature anomalies and Indian summer monsoon

In this study, the simultaneous inter-annual relationships between SST anomalies over the Northwest Atlantic Ocean and southwest monsoon rainfall over the monsoon core region have been examined using monthly SST and atmospheric data for the period 1951-2005. Statistical analyses reveal significant inter-annual simultaneous relationship between the SST anomalies over North Atlantic and rainfall over the monsoon core region, but with significant epochal variations. The relationship has become stronger after mid-1970s when the El Nino-Indian monsoon relationship has weakened. Positive SST anomalies over the North Atlantic Ocean shift the North Atlantic Jet northwards and the associated circulation changes in the upper troposphere influence Indian monsoon through the circumglobal teleconnection across central Asia. The present study, thus highlights the important role of North Atlantic Ocean as an important source of inter-annual variability of the Indian summer monsoon

The Indian monsoon: 5. Prediction of the monsoon

In this article we first consider the importance of prediction of the monsoon, and events such as the intense rainfall event over Mumbai in July 2005. We then discuss how meteorologists make short-, medium-, and long-range forecasts and the concept of the limit of predictability in a chaotic system such as the atmosphere. Problems and prospects of prediction on different time-scales are discussed by using one example of short-range forecasts and the prediction of the monsoon by dynamical and statistical methods. Finally we consider measures of the skill of a forecast and how high the skill has to be for it to be useful for applications