Progress of Indian summer monsoon onset and convective episodes over Indo-Pacific region observed during 2009-2014

Summer monsoon onset progress from the oceanic region of Southeast Bay of Bengal / Andaman Sea (Oceanr) up to extreme southwestern part of India (Kerala) for the years 2009 to 2014 is investigated. Synoptic weather information, INSAT/KALPANA-1 as well as cloud imageries archived from Dundee Satellite Receiving Station for May and early June for these years are used in the analysis. Upper-air reanalyzed winds from NCEP/NCAR and OLR data archived through NOAA satellites are also used. During the study period, the dates of monsoon onset as well as the time required for the advancement of onset from Oceanr to Kerala have shown a large variation. An attempt is made to investigate the causes for such variations. The results indicate that intense disturbances which formed over north Indian Ocean in 2009, 2010, 2013 and 2014 and over west-north Pacific Oceanic region in 2011 and 2012 have contributed for the same. Analysis is carried out, limiting its focus to bring out the role of these convective events in the observed variation of onset timing and its progress by taking case to case review of these events and bringing out their influence through synoptic analysis. Utility of this information in prediction of the progress of Indian summer monsoon onset is also brought out

On some aspects of initialization and forecasts in the Indian monsoon region.

Application of a dynamic initialization scheme for balancing initial wind and pressure fields for a one-level primitive equation model in the Indian region has been investigated. For this purpose, the model equations are integrated forward and backward around the initial time following the Euler backward time-difference scheme without restoration of any variable. For comparison, the initial wind-pressure balance has also been constructed from the observed horizontal motion field by a hierarchy of models of increasing complexity, using the geostrophic relation, the linear balance equation and the nonlinear balance equation. Furthermore, the 48 h forecasts are prepared using the balanced initial data derived from the static nonlinear balance equation and the dynamic initialization scheme. The forecast results from both initialization schemes are compared and discussed. The results obtained from the dynamic initialization scheme are found to be either slightly superior or comparable to those based on the static initialization scheme

Some flow features of the Indian summer monsoon deduced from Nimbus II radiation data

Radiation data obtained from Nimbus-II MRIR (10–11μ) and HRIR (3.5–4.1μ) radiometer for 14–19 June 1966, over the Indian Ocean are used to study some features of the monsoon circulation during the six-day period. Low values of radiation which are associated with cloudiness show two distinct features from 15–17 June: (i) a very extensive band of approximately 1000 km in width at the equator between 50°–60° E extending towards both hemispheres, and (ii) a synoptic-scale cell covering the equatorial region approx. between 70°–90° E and 0°–10° S. The two cloud systems are separated from each other by a wide region of high radiation indicating clear conditions. Sub-synoptic scale features could be detected in the radiation field (which in turn are related to the cloud field). Northern and Western sections of the Arabian Sea were relatively cloud-free. An attempt is made to relate the cloud fields with computed vertical motion fields. Areas of upward motion seem to coincide well with centers of low radiation (clouds) and those of subsidence with regions of high radiation. Horizontal flow features related to the computed vertical motion fields are discussed in the pape

A composite energetics study for contrasting south west monsoon years in the recent decade

An attempt has been made to make a composite energetics study for the three contrasting types south west monsoon season (SWMS) over India, viz. marginally normal SWMS (2000 and 2001 when seasonal total rainfall was very close to 90), normal SWMS (2003, 2005, 2006, 2007 and 2008 when seasonal total rainfall was very close to 100 of its long period average) and deficient SWMS (2002, 2004 and 2009, when seasonal total rainfall was less than 90 of its long period average). For that, decadal average for the decade 2000-2009 and anomaly, based on above decadal average, for individual year of this decade, of different energy terms, their generation and conversion among different terms have been computed daily during 1 May-30 September in the recent decade (2000-2009) over a limited region between 65°E to 95°E, 5°N to 35°N. These computations are based on daily NCEP 2.5°x 2.5°data during 1 May-30 September of the above ten years. The composite of these anomalies have then been constructed for the deficient monsoon years (2002, 2004 and 2009), marginally normal monsoon years (2000 and 2001) and for the normal monsoon years (2003, 2005, 2006, 2007 and 2008). In the decadal average, a steady fall in C(A Z, K Z) and C(A E, K E) till August and steady rise in C(A Z, A E) till July are noticed, indicating a suppressed mean monsoon circulation due to the influence of mid latitude baroclinic westerly systems. Analysis of the composite anomaly of different energetics parameter indicates that the deficient SWM, in the decade under study, are characterized by weaker mean monsoon circulation, as compared to normal or marginally normal SWM, in daily, monthly and seasonal scale, due to anomalous influence of mid latitude baroclinic westerly systems

A study of the empirical functions of the height fields over India and their relation with the rainfall

The empirical orthogonal functions have been obtained for the individual summer monsoon (June through September) months using the grid point values of monthly 700 mb geopotential heights over Indian region. The data for 21 summer monsoon months for the years 1958 to 1978 have been used in the present computation. The major variance reduction is due to the first three dominant functions accounting over 80 of the total variance in each month. The variance reduction only due to the first function ranges from 45 to 65. The first function has in-pbase oscillation throughout the area indicating that the area under study is homogeneous and the centre of the oscillation lies over northwest India. The amplitudes of the first function also show generally quasipers stence in their sign within a season. The second function has two centres of action over the region of monsoon trough which are in phase. The third function has also two centres oriented in the east-west direction but they are in the opposite phase. Fairly large values of correlation coefficients between the patterns of the different monsoon months suggest that the patterns for these months corresponding to the first and the second functions respectively are quite similar. The patterns for these months also evolve with time in a related way. The spectrum analysis to the time series of amplitudes indicates the presence of the quasi-periodicity of 3 years during these monsoon months. The amplitudes corresponding to the dominant functions are found to be significantly related with the rainfall of central and western parts of Indi

A review of stochastic dynamic method of weather prediction

The stochastic dynamic method of weather prediction (SDP) has been suggested recently for better understanding of the numerical weather prediction. The SDP is described using a simple one-dimensional advection equation. The salient features of the method, its scope and limitations, are discussed

Genesis of the monsoon trough boundary layer experiment (MONTBLEX)

This paper sets out the motivation for carrying out an observational experiment on the atmospheric boundary layer along the monsoon trough, in the light of earlier studies of the atmospheric boundary layer in India and elsewhere, and the significant role that the trough has been shown to play as a key semi-permanent feature of the southwest monsoon. The scientific objectives of the experiment are set out, and its planning and execution are touched upon. Some of the gains resulting from the experiment are mentioned, and lessons for the future about the conduct of such programmes are drawn

Comparative study of the fourier analysis procedure and Cressmans method in objective analysis of the wind field

The value of a meteorological parameter at a grid point can be derived from Fourier analysis of data at station observations around the grid point. But the inhomogeneity of data distribution does not warrant such an elaborate and rigorous approach. Cressman's method which is shown as a simplified version of local-point Fourier analysis is found to be more feasible from rms error statistics of wind field analyses by both methods

Experimental real-time multi-model ensemble (MME) prediction of rainfall during monsoon 2008: Large-scale medium-range aspects

Realistic simulation/prediction of the Asian summer monsoon rainfall on various space-time scales is a challenging scientific task. Compared to mid-latitudes, a proportional skill improvement in the prediction of monsoon rainfall in the medium range has not happened in recent years. Global models and data assimilation techniques are being improved for monsoon/tropics. However, multimodel ensemble (MME) forecasting is gaining popularity, as it has the potential to provide more information for practical forecasting in terms of making a consensus forecast and handling model uncertainties. As major centers are exchanging model output in near real-time, MME is a viable inexpensive way of enhancing the forecasting skill and information content. During monsoon 2008, on an experimental basis, an MME forecasting of large-scale monsoon precipitation in the medium range was carried out in real-time at National Centre for Medium Range Weather Forecasting (NCMRWF), India. Simple ensemble mean (EMN) giving equal weight to member models, biascorrected ensemble mean (BCEMn) and MME forecast, where different weights are given to member models, are the products of the algorithm tested here. In general, the aforementioned products from the multi-model ensemble forecast system have a higher skill than individual model forecasts. The skill score for the Indian domain and other sub-regions indicates that the BCEMn produces the best result, compared to EMN and MME. Giving weights to different models to obtain an MME product helps to improve individual member models only marginally. It is noted that for higher rainfall values, the skill of the global model rainfall forecast decreases rapidly beyond day-3, and hence for day-4 and day-5, the MME products could not bring much improvement over member models. However, up to day-3, the MME products were always better than individual member models

Aluminum Bronze Alloys to Improve the System Life of Basic Oxygen and Electric Arc Furnace Hoods, Roofs and Side Vents.

Energy Industries of Ohio was the lead organization for a consortium that examined the current situation involving the service life of electric arc and basic oxygen furnace hoods, roofs and side vents. Republic Engineered Products (REP), one of the project partners, installed a full-scale Al-Bronze “skirt” in their BOF at their Lorain OH facility, believed to be the first such installation of this alloy in this service. In 24 months of operation, the Al-Bronze skirt has processed a total of 4,563 heats, requiring only 2 shutdowns for maintenance, both related to physical damage to the skirt from operational mishaps. Yearly energy savings related to the REP facility are projected to be ~ 10 billion Btu's with significant additional environmental and productivity benefits. In recognition of the excellent results, this project was selected as the winner of the Ohio’s 2006 Governor’s Award for Excellence in Energy, the state’s award for outstanding achievements in energy efficiency