Ahead of today's opening session, the air temperature is 27 degrees C, while the track temperature is 29 degrees. It is bright and sunny, while humidity is 67 percent.

Two test drivers are taking part in this morning's session, di Resta replaces Liuzzi at Force India while Fairuz Fauzy stands in for Heikki Kovalainen at Lotus.

When the pitlane lights go green it is local her Fauzy who leads the way, followed by di Resta, Trulli, Sutil, Buemi, Alguersuari, de Grassi and Senna.

While the majority of the drivers head back into the pits after their installation lap, di Resta and Sutil both stay out for one more lap. Five minutes into the session, all but Hamilton have made an appearance.

Sauber's Pedro de la Rosa posts the first time of the day, the Spanish veteran crossing the line at 1:53.855. Meanwhile, Hamilton heads down the pitlane.

Tyre options this weekend are hard (prime) and soft (option), though some claim that it might well turn out to be wet (prime) and monsoon (option).

Fauzy posts 43.456, the Malaysian Lotus driver the only man on track at present. In the Red Bull garage, mechanics are working furiously on Webber's car, which is already said to be showing signs of overheating.

As Fauzy posts 41.745, Karun Chandhok heads down the pitlane in the Hispania. The Indian youngster subsequently posts 45.811 to go second.

Alguersuari goes quickest in the first two sectors, finally crossing the line at 40.119 as Senna goes fourth (44.926).

Next time around, Alguersuari improves by over a second, raising the benchmark with a 39.114. di Resta and Trulli also on track, the Italian demonstrating that parts of the track, particularly the final corner.

di Resta goes second with a 38.557 as Alguersuari, now on 37.478, reports a problem with his engine. Trulli goes third (41.007), ahead of Fauzy, Chandhok, Senna, Petrov and de la Rosa.

As Hulkenberg and Kobayashi head down the pitlane, di Resta goes quickest with a 37.209 and Petrov improves to third (38.476).

Thirty-four minutes into the session, Massa is the first of the big guns to come out for a second run. Hulkenberg goes third (39.244) only to be leapfrogged by Kobayashi (38.595).

Massa goes fourth (37.653) as Petrov improves to second with a 37.362. Elsewhere, Button and Kubica are on track as Fauzy has a long, long sideways slide in the Lotus making full use of the very generous run-offs here.

Button goes second (37.332), only to be demoted by de la Rosa and Kubica, who posts a 36.718 to go quickest. Moments later it's a Renault 1-2 as Petrov goes quickest with a 36.712.

Button goes quickest in all three sectors finally posting 35.464, Kubica improving with a 36.078.

Vettel goes eleventh (38.386) as Webber, Rosberg and Hamilton leave the pits.

On his first flying lap, Hamilton goes third (36.320), going quickest next time around with a 35.138. A 36.658 sees Vettel go fourth.

At halftime, it's: Hamilton, Button, Kubica, Vettel, Petrov, Kobayashi, di Resta, de la Rosa, Massa and Webber. All but Alonso and Schumacher have posted times, though the Spaniard is on track.

As Hamilton raises the benchmark with a 34.921, Webber gets well out of shape as he overtakes Barrichello at Turn 9.

Alonso's first flying lap sees the Spaniard go twenty-third with a 43.496. Still no sign of Schumacher other than his installation lap.

Rosberg improves to fifth with a 35.937 behind former teammate Webber (35.765). Next time around the German improves with a 35.463.

A 36.212 sees Alonso improve to sixth only to be demoted by Sutil (35.955).

In the Mercedes garage Schumacher is watching the telemetry monitors, keenly studying the progress of his teammate.

Moments after his teammate runs wide, de la Rosa goes off into the gravel at Turn 12, however, the Spaniard is able to drive through the kitty litter and continue. Hulkenberg also runs wide, the German looking for a decent result this weekend after miserable outings in Bahrain and Australia.

With twenty-eight minutes remaining, Schumacher leaves the pits, the German one of just six drivers on track.